Animal Body Systems

1
Animal Body Systems
2
Skin Protects the Body

• Integument comes from the Latin word integumentum
  , meaning "cover" or "enclosure."
• In animals an integument is any natural outer
  covering, such as skin, shell, or membrane.

• The skin makes up 12-15 of body weight and has a
  surface area of 1-2 meters

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Skin Protects the Body

• The human integumentary system is an external
  body covering, but also much more. It protects,
  nourishes, insulates, and cushions. It is
  absolutely essential to life. Without it, an
  individual would be attacked immediately by
  bacteria and die from heat or freezing and water
  loss.

• The integumentary system is composed primarily of
  the skin and accessory structures including hair,
  nails, and certain exocrine glands (glands that
  have ducts or tubes that carry their secretions
  to the surface of the skin or into body cavities
  for elimination).

4
Skin Layers

• A flexible and responsive organ
• An organ is any part of the body formed of two or
  more tissues that performs a specialized
  function. As an organ, the skin is the largest
  and heaviest in the body

• Composed of 2 principal layers
• Epidermis outer most layer
• Dermis inner thicker layer
• Beneath the dermis lies the subcutaneous layer or
  hypodermis, composed of adipose or fatty tissue.
  Although not technically part of the skin, it
  does anchor the skin to the underlying muscles
  and contains the major blood vessels that supply
  the dermis and houses many white blood cells,
  which destroy foreign invaders that have entered
  the body through breaks in the skin.

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Functions of the Skin

• Just think about the differences in the skin of a
  fish, a lizard, a frog, a bird, and a mammal.
• Scales, slime, feathers, and hair are all parts
  of the integumentary systems for animals.
• The skin protects the underlying organs. The fur
  helps insulate against heat loss. Dogs and cats
  do not sweat through their skin. They only sweat
  from their footpads and nose. They lose water by
  panting rather than sweating.

Fish
Snake
Bird
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Epidermis

• Outer most layer made up of an interior and an
  exterior part
• Exterior consists of 25 30 layers of dead,
  flattened cells that are continually shed
• These dead cells contain keratin, a protein fiber
  that protect the underneath layers from exposure
  to bacteria, heat and chemicals.

7
Epidermis

• The epidermis consists of stratified squamous
  epithelial tissue.
• Epithelial tissue covers the internal and
  external surfaces of the body and also forms
  glandular organs.
• Squamous cells are thin and flat like fish
  scales.
• Stratified simply means having two or more
  layers.

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• In short, the epidermis is composed of many
  layers of thin, flattened cells that fit closely
  together and are able to withstand a good deal of
  abuse or friction. It is also waterproof because
  keratin, a protein is produced.

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Epidermis

• The epidermis can be divided into four or
  five layers. Most important of
  these are the inner and outer
  layers.
• The inner or deepest cell layer is the only layer
  of the epidermis that receives nutrients (from
  the underlying dermis). The cells of this layer,
  called basal cells, are constantly dividing and
  creating new cells daily, which push the older
  cells toward the surface. Basal cells produce
  keratin, an extremely durable and water-resistant
  fibrous protein.

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Epidermis

• Another type of cell found in the lower epidermis
  is the melanocyte.
• Melanocytes produce melanin, a protein pigment
  that ranges in color from yellow to brown to
  black.
• The amount of melanin produced determines skin
  color, which is a hereditary characteristic.
• The melanocytes of dark-skinned individuals
  continuously produce large amounts of melanin.
  Those of light-skinned individuals produce less.
  Freckles are the result of melanin clumping in
  one spot.

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Epidermis

• The outermost layer of the epidermis
  consists of about twenty to thirty rows
  of tightly joined flat dead cells.
  All that is left in these cells is their
  keratin, which makes this outer layer waterproof.
  
• It takes roughly fourteen days for cells to move
  from the inner layer of the epidermis to the
  outer layer. Once part of the outer layer, the
  dead cells remain for another fourteen days or so
  before flaking off slowly and steadily. Therefore
  every 28 days all of the cells of the epidermis
  are replaced by new cells.

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Dermis

• The dermis, the second layer of
  skin, lies between the epidermis
  and the subcutaneous layer.
  Thicker than the epidermis, the dermis
  contains the accessory skin structures.
  Hair, sweat glands, and
  sebaceous (oil) glands are all rooted in the
  dermis. This layer also contains blood vessels
  and nerve fibers. Nourished by the blood and
  oxygen provided by these blood vessels, the cells
  of the dermis are alive.
• Connective tissue forms the dermis. Bundles of
  elastic and collagen (tough fibrous protein)
  fibers blend into the connective tissue. These
  fibers provide the dermis strength and
  flexibility.

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Dermis

• Thickness of the epidermis varies in different
  parts of the body depending upon the function
• Thickest on your palms and soles of your feet

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Hair Follicles

• Hair grows out of narrow cavities of the dermis
  called hair follicles that are supplied with
  blood vessels and nerves and are attached to
  muscle tissue
• Many hair follicles have an oil gland associated
  with them and if the gland is blocked by oil and
  dead cells a pimple forms

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Dermis

• The upper layer of the dermis has
  fingerlike projections that extend
  into the epidermis. Called dermal
  papillae, they contain blood
  capillaries that provide nutrients for
  the basal cells in the epidermis. On the skin
  surface of the hands and feet, especially on the
  tips of the fingers, thumbs, and toes, the dermal
  papillae form looped and whorled ridges. These
  print patterns, known as fingerprints or
  toeprints, increase the gripping ability of the
  hands and feet. Genetically determined, the
  patterns are unique to every individual.

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Dermis

• Within the dermis are sensory receptors for the
  senses of touch, pressure, heat, cold, and pain.
  A specific type of receptor exists for each
  sensation. For pain, the receptors are free nerve
  endings. For the other sensations, the receptors
  are encapsulated nerve endings. The number and
  type of sensory receptors present in a particular
  area of skin determines how sensitive that area
  is to a particular sensation. For example,
  fingertips have many touch receptors and are
  quite sensitive. The skin of the upper arm is
  less sensitive because it has very few touch
  receptors.

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Functions of the Integumentary System

• Helps maintain homeostasis by regulating internal
  body temperature
• Temperature rises, capillaries dilate and blood
  flow increases allowing more heat to be lost by
  radiation
• Cold makes capillaries constrict and heat is
  conserved
• Sweat is produced as a response to increased body
  temperature heat lost in evaporation body
  cools
• Sense organ nerve cells receive relay
  information
• Vitamin production UV light exposure produces
  Vitamin D
• Protective layer shields chemicals and physical
  damage
• Cuts allow bacteria to enter - skin repairs
  itself quickly

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Skin Diseases and Problems
Cowpox Lesion

Dermoid cyst, dog
Malignant melanoma, hamster
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Pityriasis rosea lesion on pigs hind limb. Note
the small ring-like early stage lesions the
older expanding larger rings healing centrally as
they expand.
Squamous cell carcinomas
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Vocabulary Words

• Melanocytes
• Melanin
• Sebaceous glands
• Collagen
• Hair follicles
• Keratin
• Basal cells

• Integument
• Epidermis
• Dermis
• Subcutaneous layer /hypodermis
• Stratified squamous epithelial tissue

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Musculoskeletal System

• The musculoskeletal system consists of the bones,
  cartilage, muscles, ligaments, and tendons.
• All vertebrates have a Musculoskeletal System
• Primary functions of the musculoskeletal system
  include support, motion, protection of vital
  organs, and production of blood cells.
• The skeletal system serves as the main storage
  system for calcium and phosphorus and contains
  critical components of the hematopoietic system.

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Bones
23
Bones
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Bones

• Human skeleton has 206 bones (22 bones in human
  skull)
• Skeleton has two main parts
• Axial skeleton includes the skull and bones that
  support it (skull, hyoid bone, vertebral column,
  ribs, sternum, etc)
• Appendicular skeleton (hangs) includes bones of
  the extremities and structures associated with
  them such as the shoulder and hip bones, pelvic
  girdle, wrists, ankles, fingers and toes
• Bone is a connective tissue and one of the
  hardest tissues in the body
• Common name of bones differ from medical names

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Bone Structure

• Most bones made of 6 kinds of tissue
• Spongy bone
• Compact bone (solid bone)
• Cartilage
• Ligament
• Marrow
• Outer Membrane

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Bone Structure

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Compact and Spongy Bone

• Bones are composed of two types of tissue
• Compact strong, hard outer layer surrounding
  every bone
• Stores calcium
• Spongy contains many holes and spaces
• Found towards the end of bones
• Strong and gives bone strength
• Stores calcium too
• Birds have more bone than other vertebrates
  (lightens skeleton)

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Haversian Canal

• Haversian canal or osteon are tubular structures
  that run the length of the bone
• Osteocytes are live bone cells that receive
  oxygen and nutrients from small blood vessels

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Cartilage

• Form of connective tissue that is more elastic
  and softer than bone
• Articular cartilage covers the joint surfaces of
  bone
• Meniscus is a curved fibrous cartilage found in
  some joints that serves as a cushion to forces
  applied to the joint

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Ligaments and Tendons

• Ligaments are bands of tough, fibrous connective
  tissue connecting two bones
• Usually found at bone joints where bones connect
• Tendons are thick bands of fibrous connective
  tissue that connects muscles to bones

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Marrow

• Produce blood cells in the bone marrow (the soft
  center of the bone)
• Red marrow hematopoietic (blood forming) -
  found in the humerus, femur, sternum, ribs,
  vertebrae pelvis - produces red blood cells,
  white blood cells, and cell fragments for blood
  clotting
• Yellow marrow consists of stored fat cells

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Outer Membrane

• Thin sheet of tissue that covers bone
  Periosteum
• Growth area for bone
• Many nerves and blood vessels supply the bone
  through the membrane
• This is the part that hurts when the bone is
  bumped or bruised

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Joints

• Joint articulation (join together allowing
  motion)
• A joint is found where 2 or more bones meet
• Facilitate movement

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Joints

• Joints held in place by ligaments tough bands
  of connective tissue
• Movable joints bone ends covered in cartilage
  makes movement smooth
• Bursae are fluid filled sacs that act like a
  cushion in areas with friction. They are found on
  the outside of the joint decreasing friction and
  keeping bones and tendons from rubbing against
  each other

35
Joint Types

• Joints are classified based on the degree of
  movement they allow
• The ball-and-socket joint is found in hip-bones
  and shoulders allows the most movement of all
  the joints. One bone (like the femur) has a
  ball-like knob at the end of it, the knob fits
  into a cup-like space on the other side. The
  ball-and-socket joint is what allows baseball
  pitchers to throw a ball with tremendous speed.
• The sliding joint is found in the vertebral
  column and allows small sliding movements. The
  vertebrae have pads of cartilage between them,
  and the bones slide over these pads. This is what
  makes the backbone so flexible.

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Joint Types

• The pivot joint allows movement turning from side
  to side, and your head is attached to your
  vertebral column with this joint. A hole in one
  bone fits over a pointed part of the other bone,
  so that one bone can turn on top of the other.
• The hinge joint allows bones to move back and
  forth, and is found in your elbow and knee. It
  allows bones to move like a hinge in a door.

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• 1. fixed joint 2. pivot joint 3. ball-and-socket
  joint
• 4. sliding joint 5. hinge joint

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Formation of Bone

• Ossification is the formation of bone from
  fibrous tissue
• Vertebrate skeletons are made of cartilage when
  they are born

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Formation of Bone

• Humans begin to replace the cartilage with bone
  by the 9th week
• Blood vessels penetrate the membrane covering the
  cartilage and stimulate its cells to become bone
  cells called osteoblasts

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Formation of Bone

• Osteoblasts are immature bone cells that produce
  bony tissue
• Osteoblasts secrete collagen to which minerals
  (calcium salts, etc) are deposited turning the
  osteoblasts into osteocytes
• Adult skeleton almost all bone except for where
  flexibility is needed (nose tip, external ears,
  discs between vertebrae and movable joint linings)

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Bone Growth

• Bone tissue is alive and made of cells
• Growth occurs in length and diameter
• Length at ends of bones in cartilage plates
• Diameter at outer surface
• Increased production of sex hormones during teen
  years causes rapid osteoblasts cell division
  resulting in a growth spurt
• After growth stops, bone-forming cells
  responsible for repair and maintenance of bone
• Bone Growth Movie

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Functions of the Skeletal System

• Provides a framework for body tissues
• Protection of internal organs(heart, lungs,
  brain)
• Skeleton provides attachment points for muscles

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Bones Store Minerals

• Store calcium and phosphate among other minerals
• Calcium responsible for bone strength
• Sources milk, yogurt, cheese, lettuce, spinach
  and dark leafy vegetables

Bone Minerals
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Injury Diseases of Bones

• Forcible twisting of a joint is a sprain and the
  injury occurs at the bursae, ligaments, or
  tendons
• Arthritis is an inflammation of the joints caused
  by infections, aging or injury
• Bone spurs are outgrowths of bone (form of
  arthritis)
• Osteoporosis loss of bone volume and mineral
  content causing bones to become more porous and
  brittle
• Broken bones bones are realigned and
  immobilized until bone tissue regrows

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Diseases and Injuries of the Musculoskeletal
System

• Because many body systems, including the nervous,
  vascular, and integumentary systems, are
  interrelated, disorders of one of these systems
  may also affect the musculoskeletal system and
  complicate diagnosis.
• Diseases of the musculoskeletal system most often
  involve motion deficits or functional disorders.
  The degree of impairment depends on the specific
  problem and its severity. Skeletal and articular
  disorders are by far the most common.

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• Tendons act as bridging and attachment structures
  for the muscles
• Some bridge long gaps between the muscles and
  target bone and, therefore, are prone to injury
  themselves.
• An example is the superficial flexor tendon of
  horses, which is frequently injured by partial
  tearing that leads to tendinitis.
• Another acquired tendon injury involves traumatic
  disruptions. Due to the relatively poor blood
  supply of both tendons and ligaments, healing is
  delayed and frequently poor.
• Management of injuries to ligaments and
  tendons requires patience and long-term
  rehabilitation.

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• Bone diseases are generally congenital or
  hereditary, nutritional, or traumatic.
• Congenital disorders include in utero
  malformations and atavisms, such as polydactyly
  or persistent ulnae or fibulae in foals
• Genetic defect examples are atlanto-occipital
  malformations in Arabian horses or certain cases
  of spinal ataxia, canine hip dysplasia, and
  abnormal bone formation such as that caused by
  parathyroid hypoplasia.

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Bilateral hip dysplasia in a dog
Normal hips in a dog
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• Nutritional diseases are caused primarily by
  imbalances or deficiencies in minerals
• particularly copper, zinc, and magnesium.
• Calcium and phosphorus concentrations must also
  be present in the correct ratio.
• Osteomalacia is an example of imbalanced or
  deficient calcium and phosphorus intake.
• Other nutritional disorders are caused by
  excessive protein intake of growing animals.
• Either deficiency or excess intake of some
  vitamins (vitamins A and D) may influence growth
  and development of bone (Rickets)
• Aseptic physitis or special osteochondrotic
  conditions may be caused by zinc toxicity or
  copper deficiency.

Osteoporosis
ossification of the cartilage
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Symptoms Of Rickets
Osteomalacia
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• Traumatic causes of bone disorders represent the
  vast majority of cases and including fractures,
  fissures.
• Lack of weight bearing, reduced motion,
  instability, pain, heat, or swelling usually
  accompany these disorders.
• Diagnostic procedures include inspection, manual
  palpation, diagnostic imaging (such as
  radiography, ultrasonography, or thermography,
  and increasingly scintigraphy, computed
  tomography, or MRI), and diagnostic anesthesia to
  determine the specific anatomic structure or
  region involved in the problem.

PET Scan (top) and Thermography of a cat are
branches of Nuclear Medicine that uses
radioactive isotopes
52

• Chronic inflammation of joints and surrounding
  structures is most common in articulations
  associated with locomotion, although other joints
  may occasionally be affected.
• Normal synovial fluid lubricates the synovial
  tissues in a joint by lubrication and the
  articular cartilage.

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Vocabulary Words

• Cartilage
• Axial Skeleton
• Appendicular skeleton
• Joint
• Ligament
• Bursa
• Tendon
• Compact bone
• Osteoblast
• Red marrow
• Yellow marrow

• Osteocyte
• Spongy bone
• Compact bone

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Muscles

• Half of your body mass is muscle
• Humans have more than 600 muscles
• Muscular system is all the muscles in your body
• Muscles are groups of fibers or cells that are
  fused together in a bundle
• They can change their shape and length to cause
  movement

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Muscle Types

• Three types of muscle fibers
• Smooth muscle
• Cardiac muscle
• Skeletal muscle
• Each has a different structure and pattern that
  make it different from the others

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Smooth Muscle

• Found in walls of your internal organs and blood
  vessels, digestive and reproductive tracts
• Made of sheets of cells that are elongated and
  spindly
• Not connected to bone
• Most common function involuntary muscle
  movement - squeeze so that pressure is exerted on
  the inside of the tube or organ it surrounds to
  move material through it (peristalsis, movement
  of gametes)
• Spindle shaped with one nucleus per cell

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Cardiac Muscle

• Involuntary muscle (you cant control your
  brain controls) that makes up your heart
• Tightly interconnected and form a network that
  allows the heart to contract efficiently
• Not connected to bone
• Conducts electrical impulses necessary for
  rhythmic contraction
• Bundles of fibers striated (striped from 2 kinds
  of proteins that make it up)

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Skeletal Muscle

• Attached to bones for movement
• Majority of muscle in body is skeletal muscle
• Voluntary muscle movement is under your control
• Striated two kinds of proteins make it up
• Most meats that you eat are skeletal muscle

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Skeletal MuscleFilaments
60
Skeletal Muscle Contraction

• Most work in opposing pairs
• Muscles can only shorten
• Takes a pair of muscles to move bones back and
  forth
• One muscle contracts the other in the pair
  relaxes
• Muscles made of muscle fibers that are long fused
  muscle cells
• Involuntary muscles must be stimulated by a nerve
  impulse
• Muscles only move when a muscle is contracted
• Contraction shortens the muscle

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Fast and Slow Twitch

• Fast Twitch (Type II) uses anaerobic metabolism
  to create fuel good for short bursts of
  strength fire more rapidly Two types (Olympic
  Sprinters have 80 fast twitch fibers)
• Type IIa intermediate fast twitch use aerobic
  and anaerobic metabolism and are a combination of
  Fast and Slow Twitch muscle fibers
• Type IIb Uses anaerobic metabolism to produce
  powerful, quick bursts of speed but fatigues fast
• Slow Twitch (Type I) fire more slowly muscles
  more efficient at using O2 to generate more ATP
  for constant muscle contractions can go a long
  time before they fatigue (marathon runners)

Fast
Slow
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Myofibrils

• Myofibrils are smaller units of muscle fiber that
  is composed of thick myosin protein filaments and
  thin actin protein filaments
• Myofibrils can be divided into sections called
  sarcomeres (functional unit of muscle)

63
Muscle Contractions

• Connected to bone by tendons
• Tendons cause the bone to be pulled when the
  muscle contracts
• When you flex your muscles you are contracting
  them they bulge through the skin

64
Sliding Filament Theory

• Explanation of how muscle contraction occurs
• When signaled, the actin filaments within each
  sarcomere slide toward one another, shortening
  the sarcomeres in a fiber and causing the muscle
  to contract
• Myosin filaments do not move

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Muscle Strength and Exercise

• The number of muscle fibers in a muscle are fixed
  when you are born
• Strength depends upon the thickness of the fibers
  on how many contract at one time
• Regular exercise stresses muscle fibers slightly
  and to compensate for this added workload, the
  fibers increase in diameter by adding myofibrils
• Regular exercise improves muscle performance

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Lactic Acid

• Muscle cells continuously supplied with ATP from
  aerobic and anaerobic processes
• Anaerobic processes form lactic acid that builds
  up in muscle cells.
• Acid moves into the blood increasing respiration
  rate blood becomes more acidic
• Lactic acid broken down when excess oxygen is
  produced

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Fatigued Muscles
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Vocabulary

• Actin
• Cardiac Muscle
• Skeletal Muscle
• Smooth Muscle
• Involuntary Muscle
• Voluntary Muscle
• Myofibril
• Myosin
• Sarcomere
• Sliding Filament Theory

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Cardiovascular System

• AKA Circulatory System
• Pertains to the heart and blood vessels
• Includes the heart, blood vessels and blood
• Essential to support life of each of the millions
  of cells that makes up an animal
• Blood has a wide range of functions to maintain
  the animals health
• Heart and blood provide an access path to all the
  body tissues

70
Blood Components

• Centrifuged blood separates into cellular portion
  (erythrocytes, thrombocytes, and leukocytes) and
  plasma (water and protein)
• Cellular portion of the blood makes up 30 45
  depending upon animal age and species

71
Blood Proteins

• Three types
• Albumin major blood protein water maintenance
• Draws water into blood stream by osmosis
• Produced in the liver
• Globulins
• Antibodies produced by immune system
• Fibrinogen
• Aids in clotting blood

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Cellular Component

• Three types
• Erythrocytes or Red blood cells
• Leukocytes or White blood cells
• Thromboctyes or Platelets

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Erythrocytes

• Carry oxygen
• Biconcave disk
• Produced in bone marrow erythropoiesis
• Lifespan varies Dog 100-110 days Cat 66-78 days
• Erythrocytes low in blood - kidney releases
  erythropoietin stimulating bone marrow to produce
  more RBC
• Contain Hemoglobin iron containing molecule
  that gives blood the red color

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Hemoglobin

• Efficient at binding oxygen
• carrying 97 of the oxygen
• Highest oxygen content in the lungs and it gets
  lower as it is pumped through tissues organs
• Higher CO2 concentrations in tissues lower pH
  (lactic acid) increases amount of O2 released
• Carries 20 of CO2 that is converted to
  bicarbonate and transported to the lungs
• Absorbs many free H ions lowering pH

75
Leukocytes

• Help fight infection
• 5 major types each with different functions
  Neutrophils, lymphocytes, eosinophils, monocytes,
  and basophils
• Produced in bone marrow
• Found in the blood or in tissues to fight
  infection
• A normal dog has 6000-7000 WBCs/microliter

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Neutrophils

• Phagocytize and destroy microorganisms in tissues
  and usually not in the blood
• Nucleus appears segmented or divided

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Monocyte

• Phagocytize microbes
• Produced in the marrow then move to the blood and
  into tissues
• Mature into macrophages that establish in the
  liver or lungs
• Remove microorganisms, dead cells and
  foreign particles

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Eosinophils

• Look similar to neutrophils with segmented
  nucleus
• Have a large number of visible granules in the
  cytoplasm
• Roles in fighting parasites and in allergic
  reactions
• Granules help to control inflammation

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Basophils

• Many granules with a segmented nucleus
• Involved in allergic reactions
• Some granules contain histamine
• Histamine causes inflammation in the linings of
  the nasal passages and respiratory tract
  producing sneezing and runny noses

80
Lymphocytes

• Have a single nucleus
• Produce antibodies to help fight disease
• Make up a portion of globulin found in plasma
• Found in all organs and tissues involved in
  fighting infection (tonsils, lymph nodes, spleen,
  thymus)
• Neutrophils and lymphocytes make up the largest
  number of WBCs in the circulation blood

81
Platelets

• Produced in bone marrow
• Aid in normal clotting of the blood
• Only damaged vessel stimulates a clot
• Very complicated process involving platelets and
  numerous proteins and factors in the blood
• Blood vessel is cut?vessel constricts?platelets
  begin to attach to the edges of the damaged
  vessel?clotting factors convert fibrinogen to
  fibrin completing the plug?over time fibrin is
  replaced with repaired blood vessel

82
Blood

• Useful in diagnosing disease
• Numerous blood tests available
• Hypo value below normal
• Hyper value above normal
• Anemia low red blood cell count
• Less oxygen supplied to tissues
• Fatigue during exercise usually first symptom
• 3 common causes
• excessive blood loss
• Shortened RBC life span
• Decreased RBC production
• Body attempts to correct anemia by releasing as
  many RBCs as possible some immature without
  nucleus

83
Blood Clotting in Animals

• Quite impressive
• Farm cat with leg amputated by farm machinery can
  stop bleeding without intervention

84
Blood Functions

• 2 major functions
• Transport substances throughout the body
• Oxygen, carbon dioxide, nutrients, wastes,
  electrolytes and hormones
• Protect the body from infection and diseases

85
Mammalian Heart Structures

• Heart is located inside the thoracic cavity
• 4 chambered heart making 2 separate circulatory
  paths
• Pulmonary side pumps blood to the lungs
• Exchanges oxygen and carbon dioxide
• Systemic circulation delivers blood to the body
• Delivers oxygen rich blood and nutrients to the
  organs

86
Structures of the Heart

• Located low in the chest between two lungs
• Surrounded by the pericardium -thin membrane
• Pericardium filled with pericardial fluid to
  prevent friction between the heart and the
  pericardium when the heart beats
• Hollow organ divided into 4 chambers
• Valves keep blood flowing in one direction
• Present in all major vessels leaving the heart
• Muscular septum separates right and left sides

87
Heart Walls

• Heart is made of 3 walls
• Epicardium external layer of the heart
• Myocardium middle and thickest layer of the
  heart this is the actual heart muscle
• Endocardium inner layer of the heart lines
  the heart chambers and valves

88
Coronary Arteries

• Called coronary arteries because they look like a
  crown
• Supply blood and nutrients to the myocardium
• Coronary veins remove wastes from the myocardium
• Disruption of blood flow may be coronary
  occlusion (blocked)
• Ischemia is a deficiency of blood supply to an
  area
• Ischemia can lead to necrosis (death of tissue)
  the area is called an infarct (infarction)

89
Blood Vessels and Blood Flow

• Opening within a vessel is the lumen
• Diameter affected by constriction or dilation
• Vasoconstrictors and vasodilators contract or
  dilate the vessels
• Blood returns to the heart from the systemic
  circulation via large vessels called vena cava
• In front of heart blood returns by cranial vena
  cava
• Behind heart through caudal vena cava
• Human anatomy
• Superior vena cava cranial vena cava
• Inferior vena cava caudal vena cava

90
Blood Circulation

• Vena cava?right atrium?right ventricle (via right
  atrioventricular valve)?lungs (via pulmonary
  artery through pulmonary semilunar valve)?left
  atrium (via pulmonary vein)?left ventricle (via
  left atrioentricular valve)?aorta (via aortic
  semilunar valve)?arteries? arterioles?capillaries?
  veinules?veins?Vena cava

91
Heart Facts

• Blood returning through the vena cava is low in
  oxygen, high in wastes and CO2
• Valves in the heart and in major arteries leaving
  the heart keep blood from flowing backwards
• The left ventricle is the thickest wall of the
  heart

• Veins have thinner walls than arteries
• A muscular septum divides the left and right side
  of the heart
• Major branches off aorta carotid (head and
  brain), mesenteric (gastrointestinal tract),
  renal (kidneys), iliac (hind legs)

92
Heart Rate

• Rate of heartbeat is partially controlled by the
  nervous system through electrical stimulation of
  the myocardium
• Beat begins within the heart by pace maker cells
  without input from the nervous system

93
Pacemaker System

• Pacemaker system keeps heartbeat and contractions
  regular and organized
• Atrial contraction followed by ventricular
  contraction
• Mammals pacemaker called sinoatrial (SA)
  node that is found in the wall of the right
  atrium near the entrance of the
  superior vena cava
• Purkinje fibers - specialized cells in
  right atrium signal SA node to spread
  electrical signal to surrounding muscle
  cells
• Atria contract blood pushed into the two
  ventricles
• Signal picked up by the atrioventricular (AV)
  node
• Conducting fibers carry electrical stimulus to
  the ventricles and ventricles contract

94
Cardiac Cycle

• A cardiac cycle is one complete contraction and
  relaxation period
• Rate varies by species
• Pulse the rhythmic expansion and contraction of
  an artery produced by pressure created as blood
  surges through veins
• Atria fills with blood during
  relaxation or diastole phase
• Systole phase is during the
  contraction

2 complete cycles
95
Blood Pressure

• Tension exerted by blood on the arterial walls
• Blood pressure is taken during both phases of
  cardiac cycle and is measured by a
  sphygmomanometer
• Hypertension high blood pressure/hypotension
  low pressure
• Higher (first) number is during systole phase the
  second (lower) number is diastole phase

96
Blood Pressure

• Measured in mm Hg
• Human typical blood pressure is 120/80
• Blood pressure varies for each species and for
  fitness levels
• Blood pressure increases heart rate decreases
  (impulse from vagus nerve)
• Blood pressure decreases heart rate increases
  (impulse from vagus nerve)
• Pressure much higher in arteries than in veins

97
Electrocardiograms

• Flow of ions that incites cardiac muscle
  contraction causes a small electrical current
• Electrocardiograph is an instrument that measures
  these electrical currents
• Electrocardiogram (ECG) is a tracing made of the
  currents
• ECG identifies problems associated with the
  contraction of the heart
• Changes in the size of the heart or damaged
  portions can be detected by changes in the sizes
  or shapes of the peaks on the ECG

98
Heart Rhythms

• Sinus rhythm normal consistent rate rhythm
• Arrhythmia change in rate, rhythm/conduction in
  the heart
• Sinus tachycardia is a faster than normal rate
• Sinus bradycardia is a slower than normal rate
• Sinus arrhythmia heart rate increases w/inhale
  and decreases w/exhale
• Atrial fibrillation SA node not acting as
  pacemaker atria quivers instead of contracting
  correctly
• Ventricular fibrillation Site in ventricle
  fires very rapidly making the ventricle quiver
  instead of contracting. Most serious arrhythmia
  requires defibrillation
• Asystole Heart no longer contracting cardiac
  arrest

99
Heart Rate

• Several factors influence heart rate
• Disease
• Fear
• Nervousness
• Shock

100
Heart Murmurs

• Sound made by a defective valve
  or abnormal blood flow
• A swishing noise caused by a leak in a
  valve
• Results from the inability of the valve to
  perform or close properly
• AV valve leak systolic murmur (occurs during
  contraction of ventricles) lub-swish-dub
• Aortic valve leak diastolic murmur (blood
  leaking back into ventricle as it relaxes)
  lub-dub-swish

101
Cardiac Output

• Amount of blood pumped in one minute
• Capable of increasing dramatically when needed
  (ex horse running a race)
• Heart rate increases
• Amount of blood increases

• Cardiac Output in mL/min heart rate (beats/min)
  X stroke volume (mL/beat)
• An average person has a resting heart rate of 70
  beats/minute and a resting stroke volume of 70
  mL/beat. The cardiac output for this person at
  rest is
• Cardiac Output 70 (beats/min) X 70 (mL/beat)
  4900 mL/minute.
• The total volume of blood in the circulatory
  system of an average person is about 5 liters
  (5000 mL) and it is pumped through the heart
  about once a minute in a healthy adult.

102
Shock

• Inadequate tissue perfusion not enough blood
  pumped to the vital organs
• Animals are weak and depressed
• Heart rate is rapid and weak
• Low capillary refill time (press on gums and pink
  color should return in 1 second)

103
Heart Failure

• Commonly affects elderly pets specially if they
  have a heart murmur
• Heart enlarges and beats rapidly
• Cough develops from enlarged heart putting
  pressure on the airway
• Fluid accumulates in the lungs or abdomen
• Condition eventually fatal

104
Pathologic Conditions

• Artherosclerosis hardening and narrowing of the
  arteries
• Congestive heart failure retention of fluid and
  edema (fluid in intercellular spaces) as a result
  of insufficient cardiac output
• Carditis inflammation of heart
• Pericarditis inflammation of pericardium
• Myocarditis inflammation of myocardium
• Endocarditis inflammation of endocardium and
  sometimes heart valves
• Vasculitis inflammation of blood vessel
• Aneurysm balloon-like enlargement of artery
• Hemangioma benign tumor of newly formed blood
  vessels

105
Pathologic Conditions

• Thrombus blood clot attached to artery or vein
• Embolus foreign object circulating in blood
• embolism blockage of blood vessel
• Cardiomyopathy disease of heart muscle
• Hypoxia below normal oxygen levels
• Dirofilariasis heart worm infection
• Congenital present at birth
• Anomaly deviation from normal
• Idiopathic unknown cause
• Iatrogenic produced by treatment

106
Vocabulary

• Platelets
• Pericardium
• Arteries
• Veins
• Vasoconstrictor
• Vasodilator
• Hypertension
• Electrocardiogram
• Ventricles
• Atria
• Aorta
• Myocardium
• Epicardium

• Erythrocytes
• Thrombocytes
• Leukocytes
• Albumin
• Globulins
• Fibrinogen
• Hemeoglobin
• Neutrophils
• Monocyte
• Eosinophils
• Basophils
• Lymphocytes
• Endocardium

107
Respiratory System

• Brings O2 into the body and blood delivers it to
  cells
• Respiration exchange of gases between the
  atmosphere and body cells
• Ventilation breathing fresh air

108
Respiratory Tract

• The respiratory tract is divided into upper and
  lower tracts
• Upper nose, mouth, pharynx, epiglottis and
  larynx
• Lower trachea, bronchial tree and lungs

109
Upper Respiratory Tract

• Air enters and exits the body through the nose
• Nose consists of nostrils or nares that are
  paired and is divided by cartilage called the
  nasal septum
• Endotherms have nasal turbinatesscroll-like
  bones covered with vascular mucous membranes that
  warm, moisturize and filter inhaled air

110
Upper Respiratory Tract

• Lined with mucous membrane
• Mucous from glandular secretions and cilia help
  filter the air to remove debris
• Olfactory receptors, responsible for smell are
  nerve endings in the mucosal lining

111
Upper Respiratory Tract

• Sinus is a fluid or air filled sac in the bone
  that produce mucous, make bone lighter and aid
  formation of sounds
• Air passes through the nasal cavity to the
  pharynx carrying air food pharynx throat
• Pharynx connects nasal passages to larynx and
  mouth to esophagus

112
Divisions of the Pharynx

• Nasopharynx passageway of air entering through
  the nose located posterior throat to the nasal
  cavity above the soft palate
• Oropharyns - throat between the soft palate
  epiglottis air passageway
• Laryngopharynx throat below epiglottis that
  opens into the voice box and esophagus food
  entering mouths passageway

113
Other Upper Respiratory Tract Structures

• Soft Palate closes off the nasopharynx to
  prevent food from going up the nose during
  swallowing
• Epiglottis acts like a lid covering the larynx
  during swallowing to keep food from entering
  trachea and going into the lungs

114
Larynx

• Larynx is a firm cartilage structure between the
  pharynx and the trachea is called the voice box
• Opening to the major airways (you can feel yours
  at the top of your neck)
• Contains the vocal folds (cords) paired
  membranous bands in the larynx that help produce
  sound

115
Glottis

• The vocal apparatus consisting of vocal cords and
  the space between them
• Air passes through glottis causing a vibration
  that produces sound
• In avian species the syrinx is the vocal
  apparatus and it is located between the trachea
  and bronchi

116
Respiratory System

• Epithelium covered with mucus that filters the
  air by trapping particles that are eventually
  swallowed
• Mucus is moist and it keeps the lungs from
  loosing moisture
• Increases the surface area allowing air to
  contact a large amount of epithelium and the air
  warms up close to body temperature before it
  enters the lungs

117
Trachea

• Larynx leads to the trachea also called the
  windpipe
• Passes into the thorax
• Trachea is ventral to the esophagus and held open
  by a series of C-shaped cartilage rings
• Open part of C is adjacent to esophagus makes
  swallowing easier Cs joined by connective
  tissue
• Cartilage allow neck to move without pinching off
  the air flow
• Lined with smooth epithelium and mucous coated
  cilia for catching tiny particles
• Mucus with particles is worked back up to the
  larynx then swallowed

Tracheal collapse During inspiration, the
trachea in the neck tends to collapse
118
Bronchi

• Trachea enters the chest and branches into two
  major bronchi that each lead to a lung
• Bronchi divide into smaller and smaller airways
  forming the bronchioles
• divisions of Bronchi
  resemble tree branches and is
  called the bronchial tree
• Bronchioles have smooth muscle in
  their walls allowing
  airway to dilate or
  constrict

119
Bronchioles

• Bronchioles lead to smallest openings the alveoli
• Contain no cartilage or glands
• Gas exchange occurs between alveoli and blood
• Branch terminate into alveoli
• 1. Trachea 2. Mainstem bronchus 3. Lobar
  bronchus4. Segmental bronchus5. Bronchiole 6.
  Alveolar duct7. Alveolus

120
Alveoli

• Alveoli coated in surfactant that keeps them from
  collapsing and lowering the amount of pressure
  required to inflate
• Thin flexible membrane wall surrounded by
  capillaries
• Prematurely born animals may lack surfactant
  (fatal)

121
Lungs

• Thoracic cavity is contained within the ribs
• The main organ of respiration is the lungs
• Lungs are divided into lobes (well defined
  portion) and the number of lobes differs between
  species
• Area between the lungs is
  the mediastinum and is where you would
  find the heart, aorta, lymph
  nodes, esophagus, trachea, bronchial
  tubes, nerves thoracic duct
  thymus

122
Lungs

• Lungs contain an enormous collection of
  alveoli, bronchioles and bronchi
• Lungs look and feel spongy with
  air trapped and elastic connective tissue that
  holds airways together
• Lungs covered with smooth epithelial membrane
  called pleura (also lines the thorax)
• Fluid between the pleural layers provides
  lubrication to prevent friction
• In healthy animals lungs will touch the chest
  wall during inhalation

123
Diaphragm

• Muscle separating thoracic peritoneal cavities
• Causes air pressure in lungs to drop below
  atmospheric pressure producing a vacuum in
  thoracic cavity to draw in air
• Diaphragm relaxes air is forced out
• Innervated by phrenic nerve

124
Breathing

• Inhalation (Inspiration) air taken into lungs
  chest cavity volume increases
• Exhalation (expiration) air forced out of lungs
  chest cavity volume decreases
• Difficulty in breathing dyspnea

125
Inhalation

• Intercoastal Muscles between the ribs raise the
  ribs and expand the chest
• Diaphragm contracts moves towards the abdomen
• Pressure in the lungs is lowered allowing air to
  flow into the lungs

126
Expiration

• Intercoastal Muscles relax ribs lower
• Diaphragm relaxes arching forward toward chest
• Elastic tissue in lungs recoils driving air out

127
Respiration Rate

• Respiration Rate breaths per minute
• Brain controls the normal rate of respiration
• Factors influencing respiration rates
• Heat (hot day)
• Nervousness (trip to the vet)
• Activity level
• Panting (for cooling) Cools blood in
  pharynx blood vessels that lowers the
  body temp as cooler blood circulates
• Oxygen plays a small part in respiration rate
  levels must fall very low before they stimulate
  respiration but CO2 levels quickly stimulate
  respiration

128
Normal Respiration Rates Normal Respiration Rates
Animal Respiration Rate
Dog 22
Cat 26
Cow 30
Horse 12
Human 12
Sheep 19
Guinea Pig 90
Hamster 74
129
Exercise Respiration

• Muscles produce more CO2 when animal is active
  stimulating faster respiration
• Special receptors in major arteries detect the
  increase of CO2 in the blood and send signals to
  the brain
• Bronchioles are stimulated to dilate opening
  airways and improving air delivery to alveoli

130
Breathing

• Breathing is an involuntary process but it can be
  controlled consciously (ex holding your breath)

                                                
                                     Pulmonary
air-sac system of a Common Teal (Anas crecca)
with blue highlighting the location of air sacs
.b, Main components of the avian flow-through
system. Abd, abdominal air sac Cdth, caudal
thoracic air sac Cl, clavicular air sac Crth,
cranial thoracic air sac Cv, cervical air sac
Fu, furcula Hu, humerus Lu, lung Lvd, lateral
vertebral diverticula Pv, pelvis and Tr,
trachea (From O'Connor and Claessens 2005)
131
Sneezing

• A protective reflex action usually caused by the
  irritation of sensitive nerve endings in the
  mucous membrane that lines the nose
• Large amount of air forced through nose and mouth
  forcing trapped particles out
• Nasal discharge categorized by character serous
  (clear), mucoid (cloudy), blood tinged, bloody
  (epistaxis) or a combination of these.
• It is also categorized by location unilateral
  (one nostril vs. bilateral (both nostrils)
  chronicity (acute vs. chronic) and associated
  signs of disease. For example, nasal bleeding
  could suggest injury, a tumor, bleeding disorder
  or a tick-borne infection.

132
Coughing

• When foreign particles enter the larynx and
  trachea and they initiate the coughing reflex
• Air is first inhaled, then the epiglottis and
  vocal folds close and the animal begins to exhale
  forcefully opening the epiglottis and vocal folds
  allowing air to rush out with great force
• Kennel Cough - The most common cause in dogs is
  the bacteria Bordetella bronchiseptica. The
  bacteria becomes airborne when an infected dog
  breathes, barks and coughs, then the bacteria is
  inhaled by another animal, resulting in kennel
  cough transmission
• Phlegm thick mucus secreted by respiratory
  lining that is ejected through the mouth it is
  called sputum (can be used for cytologic
  examination/testing)

133
Clinical Practice

• Cyanosis blood has a darker bluish color when
  oxygen levels are too low indicated inadequate
  oxygen being delivered to tissues
• Pneumonia inflammation in the lungs usually
  caused by an infection (viral or bacterial)
• White blood cells try to fight infection cells
  and tissue fluid accumulate in alveoli decrease
  in lung capacity and effectiveness of gas
  exchange
• Bubbling sound of popping bubbles suggesting
  fluid accumulation
• Pleural friction rub - pleural noise indicating
  lungs and chest are inflamed and irritated
• Crackles and Wheezes noises that indicate
  inflammation, fluid or both in the lungs

134
Clinical Practice

• Hypoxia inadequate O2 supply to body tissues
• Hypercapnia excessive CO2 in blood (Hypocapnia
  decrease in CO2 levels in blood)
• Respiratory acidosis excessive CO2 in blood
  lowering blood pH (respiratory alkalosis
  abnormally low CO2 levels raising pH)
• Hyperventilation - abnormal increase in
  respiration rate
• Indotracheal intubation passage of a tube
  through the oral cavity, pharynx and larynx into
  the trachea
• Chest tube tube inserted into thoracic cavity
  to remove gases or fluids

135
Clinical Practice

• Cats/kittens with runny eyes, nasal discharge,
  sore throat, fever, coughing and sneezing not
  unusual for all cats in house to develop the
  symptoms since disease causing organisms are
  highly contagious
• Horses have much larger lungs than cattle of the
  same size
• Roaring one vocal fold fails to open air has ½
  opening to enter/exit
• Heaves coughing, nasal discharge, labored
  breathing and easily tire from exposure to dust
  and mold bronchodialators are given to open
  airway and decrease inflammation

136
A smoker's dissected heart and lungs show black
spots from tar.
137
Cross section of a human lung. The white area in
the upper lobe is cancer the black areas are
discoloration due to smoking
138
Vocabulary

• Respiration
• Palpated
• Endotracheal tube
• Inspiration
• Expiration
• Cyanosis
• Pneumonia
• Pleural fraction rub
• Pleura
• Thorax

• Contagious
• Bronchodialator
• Bronchioles
• Alveoli
• Ventilation
• Diaphragm
• Larynx
• Pharynx
• Epiglottis
• Soft Palate