Regulation and Homeostasis in the Human Body

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Regulation and Homeostasis in the Human
Body Overview
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How do Humans and other complex mammals maintain
homeostasis? They must carry out all needed life
functions in a coordinated way.
What does our species need to accomplish? Growth
Repair of injuries Get energy Get building
materials Get rid of waste Keep away
disease Respond to changing environment Reprodu
ce
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Eleven Body Systems work together to maintain
homeostasis and carry out these tasks 1. Nervous
System 2. Endocrine System 3. Lymphatic System
4. Circulatory System 5. Respiratory System 6.
Digestive System 7. Excretory System 8.
Skeletal System 9. Muscular System 10.
Integumentary System 11. Reproductive System
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1. Nervous System Structures Brain, Spinal
Cord, Peripheral Nerves, Neurons (Cells of
nervous system) Functions Coordinates the
bodys response to changes to internal and
external environment
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2. Endocrine System Hormone System
Structures Glands - Hypothalmus, pituitary,
thyroid, parathyroids, adrenals, pancreas,
ovaries (in females), testes (in
males) Functions Produce Hormones. Controls
growth, development, metabolism, and reproduction

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3. Lymphatic System Immune System
Structures White blood cells, thymus, spleen,
lymph nodes, lymph vessels Function Helps
protect the body from disease collects fluid
lost from blood vessels returns the fluid to the
circulatory system
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4. Circulatory System
Structures Heart, Blood vessels,
blood Functions Brings oxygen, nutrients, and
hormones to cells fights infection regulates
body temperature
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5. Respiratory System
Structures Nose, pharynx, larynx, trachea,
bronchi, bronchioles, lungs Functions Provides
oxygen needed for cellular respiration and
removes carbon dioxide from body
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6. Digestive System
Structures Mouth, pharynx, larynx, esophagus,
stomach, liver, pancreas, small and large
intestines, Function Breaks down foods into
simple molecules that can be used by the body for
respiration and building cells
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7. Excretory System
Structures Skin, lungs, kidneys (nephrons),
ureters, urinary bladder, urethra Functions
Removes waste products of metabolism from the body
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8. Skeletal System
Structures Bones, cartilage, ligaments,
tendons Functions Supports the body protects
internal organs allows movement stores mineral
reserves provides a site for blood formation
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9. Muscular System
Structures Skeletal muscle, smooth muscle,
cardiac muscle Function Works with skeletal
system to produce voluntary movement helps
circulate blood and move food through the
digestive system
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10. Integumentary System (Skin)
Structures Skin, Hair, Nails, Sweat and Oil
Glands Functions Serves as a barrier against
infection and injury Helps to regulate
temperature Protects against UV light
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11. Reproductive System
Structures Female- Uterus, Fallopian tubes,
ovary, cervical canal, cervix, vagina Male
Penis, Vas Deferens, Prostate, Epididymis,
Testes, Scrotal Sac, Seminal Vesicle Function
Produces reproductive cells in females nurtures
and protects developing embryo
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Support and Motion Functions of the SKELETAL
AND MUSCULAR SYSTEM
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How does the human body move from place to place
and have the ability to run, blink or build
things? These things are all made possible by
the skeletal and muscular systems.

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A. Skeletal System
There are 206 bones in the adult human body.
These bones provide a system of supports and
levers on which muscles can produce movement
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Bones are a solid network of living cells and
protein fibers that are surrounded by calcium
deposits. Bones contain blood vessels and
cavities containing marrow. Red marrow produces
red blood cells, white blood cells and platelets
Figure 36-3 The Structure of Bone
Bone Marrow
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Joints are places where one bone attaches to
another. Each type of joint is designed to allow
movement without damaging the other bones.
Joints in the skull allow no movement, joints in
the spine allow a small amount of movement and
those shown below allow movement in one or more
directions.
Figure 36-4 Freely Movable Joints and Their
Movements
Section 36-1
Ball-and-Socket Joint
Pivot Joint
Elbow
Hinge Joint
Saddle Joint
Knee
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Knee Joint
Section 36-1
Ligaments are a tough connective tissue that
attach bones to bones
Tendons are connective tissue which attach bones
and muscles to allow bones to move
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• B. The Muscular System
• More than 40 of the average human is muscle.
  Muscles are involved in both voluntary actions
  and involuntary actions. Three types of muscles
  cells are
• Skeletal Attached to bones for voluntary
  actions and controlled by the central nervous
  system
• Smooth Found in the digestive tract and the
  blood vessels to move food and blood. Control
  involuntary actions (you do not decide for them
  to work)
• Cardiac Heart muscle cells are involuntary.

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Figure 36-7 Skeletal Muscle Structure
Skeletal muscles are made up of clusters of
filaments of proteins known as actin and myosin
which control muscle contraction and relaxation
Section 36-2
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Figure 36-8 Muscle Contraction
During Muscle contraction Actin filaments slide
over myosin filaments shrinking the muscle
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Energy for muscle contraction is supplied by ATP
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Nervous system cells known as motor neurons are
attached to skeletal muscle cells to control the
voluntary movement.
Threadlike Nerve or neuron
Axon or junction
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Figure 36-11 Opposing Muscle Pairs
Skeletal muscles work in opposing pairs. When
one muscle contracts, the other relaxes.
Section 36-2
Movement
Biceps (relaxed)
Biceps (contracted)
Movement
Triceps (contracted)
Triceps (relaxed)
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Nutrition and Waste Removal
How does the human body take in required
nutrients and get rid of wastes? The Digestive
and Excretory Systems are responsible for
bringing in food and getting rid of the
leftovers.
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Overview of Nutrients

• Food supplies the raw materials for building
  molecules your body needs, such as
• enzymes
• Lipids in cell membranes
• DNA
• Food contains 45 substances your body needs but
  cannot manufacture.

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The nutrients your body needs are water,
carbohydrates, fats, proteins, vitamins and
minerals. WATER Most of the bodies reactions
take place in water. Humans need an average of 1
liter of water a day. Dehydration causes many
problems throughout the body. CARBOHYDRATES
Sugars and starches are used by the body to
provide the simple sugars needed for Respiration
(energy)
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FATS- Deposits of fats protect body organs,
insulate the body and store energy, make up cell
membranes and coat the nervous system
cells PROTEINS Supply the raw materials for
growth and repair in the form of enzymes VITAMINS
Organic molecules that work with enzymes to
control body processes. MINERALS Inorganic
nutrients that are needed in small amounts.
Calcium is needed to build bones, Iron is needed
for red blood cells.
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 Food Guide Pyramid
A Balanced Diet
Fats
Sugars
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C. The Digestive System
Mouth
Pharynx
Salivary Glands
Esophagus
Liver
Stomach
Pancreas behind stomach
Gallbladder
Large Intestine
Small Intestine
Rectum
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The Process of Digestion The path of food Each
organ of the digestive system helps convert foods
into simpler molecules that can be absorbed and
used by the cells of the body. Teeth Cut,
Crush and tear food Salivary glands Moisten
food to make it easier to chew and pass through
the system, enzymes break down starches Esophagus
Tube from mouth to stomach connected by
Pharynx. Works by contraction of the smooth
muscles known as peristalsis. Stomach
Muscular sac that churns and mixes food with acid
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As food leaves the stomach it travels into the
small intestine through the doudenum, and it
mixes with with enzymes and digestive fluids from
the liver, gallbladder and pancreas.
Section 38-2
Liver
Bile Duct
Gallbladder
Pancreas
Doudenum
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Chemicals from the pancreas breakdown
carbohydrates, proteins, lipids and nucleic
acids. In addition chemicals from the pancreas
produce substances which neutralize stomach acid.

.
If the acid travels too far without being
neutralized it will change the shape of enzymes
and cause problems in the body.
The Liver makes bile which acts like a detergent
to break down fat. The gall bladder is a storage
area for the bile
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The small intestine absorbs nutrients from the
digestive systems and transfers many of the
nutrients to the circulatory system. The small
intestine is lined with small fingerlike
projections known as villi which designed to have
a large surface area for this task.
Section 38-2
Small Intestine
Villus
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Large intestine (Colon) Food that enters the
large intestine is nutrient-free. Usable
nutrients have been absorbed leaving water and
undigestible substances. The large intestine
removes water from the waste. Once water is
eliminated the solid waste passes out of the body
through the rectum. The appendix is located
just below the entry to the large intestine.
In many animals it helps digest difficult
materials such as cellulose. In humans the
appendix is not used for any purpose in
digestion. When it gets infected it is
removed.
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D. Excretory System In the process of
obtaining nutrients and carrying out chemical
reactions the human body produces wastes (CO2,
Urea, Salts). If some of these wastes are not
removed they could threaten homeostasis. Excess
chemicals that are not toxic also need to be
removed. The skin, lungs and kidneys all
function to get rid of excess or harmful
products produced in the body.
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Kidneys contain millions of small filters called
nephrons, which filter your entire blood supply
every 45 minutes. Filtration takes place because
blood pressure forces water, salt, glucose, amino
acids and urea into structures known as Bowmans
capsules. (Protein and Blood are too large to
enter)
Section 38-3
Kidney
Nephron
Bowmans Capsule
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Processes of osmosis and active transport filter
the useful materials from the waste (urine).
Substances your body needs to keep are returned
to the blood stream. Substances your body needs
to get rid of are passed from the renal tubes to
the urinary bladder.
Artery
Vein
Kidney
Ureter
Urinary Bladder
Urethra
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• Other important parts of the bodies excretory
  system
• The skin excretes excess water and salts
• The lungs excrete carbon dioxide produced from
  respiration

Both of these body organs serves multiple
functions in the human body.
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The Respiratory System links to the Circulatory
System to provide cells with oxygen and remove
carbon dioxide
Figure 37-13 The Respiratory System
Section 37-3
Bronchi branch to air sacs known as aveoli where
gas exchange occurs
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Gas Exchange in the lungs occurs through the
process of
Alveoli
Section 37-3
Bronchiole
DIFFUSION
High concentration of oxygen (O2) moves out of
lungs into blood to balance concentration. CO2
does the opposite (moves from blood to lungs)
Capillary
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The Lungs are only air sacs. In order for them
to move they must work together with a muscle
known as the Diaphragm
Figure 37-15 The Mechanics of Breathing
Section 37-3
Air inhaled
Air exhaled
Rib cage lowers
Rib cage rises
Diaphragm
Diaphragm
Exhalation
Inhalation
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Breathing is not an entirely voluntary process.
While you have control of breathing so that you
can briefly hold your breath or blow up a
balloon, your body will not allow you not to
breathe. The brain has control over the
diaphragm if the level of carbon dioxide in the
blood rises to high.
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• The circulatory system works together with
  several other body systems to bring needed
  supplies to cells which cannot move. The
  circulatory system is a delivery system that
  consists of the following
• The Heart
• Blood Vessels
• Blood

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The Heart The heart is about the size of a
clenched fist. On average the heart contracts
about 72 times a minute, pumping about 70
milliliters of blood with each contraction.
The entire circulatory system including Heart has
structures which prevent oxygen rich blood and
oxygen poor blood from mixing. All blood is
really red but oxygen poor blood is shown as blue
in pictures for ease.
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The heart has four main chambers with valves that
separate each to prevent backflow
Pulmonary Artery Oxygen poor blood to lungs
Left Atrium
Left Ventricle
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The heart acts as two pumps. One for sending
oxygen poor blood to the lungs and the other for
sending oxygen rich blood to the body.
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The hearts contractions are controlled by a
small group of cardiac muscle cells known as the
sinoatrial node. These are the pacemakers of the
heart. These cells send an electrical message
from the atrium to the ventricles to contract
Sinoatrial Node
Conducting Fibers
Atrioventricular node
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Blood moves through 3 different types of vessels
Arteries Carry oxygen rich blood away from the
heart Capillaries Tiny vessels only one cell
thick. Bring oxygen and nutrients to the cells.
Remove waste products. Veins Carry blood back
to the heart with wastes

VEIN
ARTERY
CAPILLARIES
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Blood Pressure When the heart contracts it
produces pressure in the arteries. The force of
the blood on the arteries is known as blood
pressure. Blood pressure decreases when the
heart relaxes but it does not disappear. The
difference between the two pressures is what is
measured when you go to the doctor and have your
blood pressure checked. The average adults
blood pressure is 120/80.
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Blood
The Human body contains 4 to 6 liters of blood,
which is about 8 of the total body mass. Blood
is made up of a number of types of cells and
substances 55 Plasma mostly water with
dissolved gases, salts, nutrients, enzymes,
hormones, waste products and plasma
proteins. 45 Cells Red Blood cells, White
Blood Cells, and platelets.
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Plasma
Cells
Sample Placed in Centrifuge
Whole Blood Sample
Blood Sample That Has Been Centrifuged
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Red blood cells transport oxygen on an iron
containing protein called hemoglobin. They are
shaped like flat disks so that they have maximum
surface area and dont get caught in the blood
vessels.
Mature red blood cells do not have a nucleus.
Your body produces red blood cells in bone marrow
and each one circulates for about 120 days.
RBCs are destroyed by the liver and the spleen.
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Platelets and plasma proteins work together to
make sure that too much blood is not lost.
1. Injured blood vessel
2. Platelets clump at site and release Thrombin
3. Fibrin forms from Thrombin and clot stops
blood loss
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White Blood cells (also known as Leukocytes) are
also produced in the bone marrow but do not have
hemoglobin for carrying oxygen. They contain
nuclei and live anywhere from a few days to a few
months. They carry out an entirely different
function than the Red Blood Cells. White blood
cells are the army of the circulatory system.
They attack foreign substances or organisms.

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Normally the body contains 700 times more red
blood cells than white blood cells. The
body can increase the number of white blood cells
on demand if the body is threatened by a foreign
invader. Doctors often test for increased White
Blood Cell levels to check your health
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F. The Lymphatic system collects fluid that leaks
into body tissues and returns it to the
circulatory system. Lymph nodes are also filters
that collect invaders that cause disease.
Thymus
Superior Vena Cava
Heart
Thoracic Duct
Spleen
Lymph Nodes
Lymph Vessels
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• G. The Integumentary system or Skin is the bodies
  largest organ. It serves many purposes and
  overlaps with many of the body systems.
• Serves as a barrier against infection and injury
• Helps regulate body temperature
• removes excess salts and water
• Protects internal cells from UV radiation
• Serves as one link between the nervous system
  and the environment (receives information on
  pressure, temperature, pain)

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• The skin is made of 2 main layers
• 1. Epidermis Outer layer of skin which comes
  in contact with environment.
• The outermost layer is coated in dead cells.
• The inner epidermis rapidly divides to produce a
  constant supply of new cells, constantly pushing
  old cells to the top.
• As skin cells are forced upward they flatten
  and organelles disappear and they form a layer of
  waterproof covering

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2. Dermis Inner layer of the skin containing
blood vessels, nerve endings, sweat glands, oil
glands, sense organs, hair follicles.
Epidermis
Dermis
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• Hair and Nails are made up of a substance known
  as keratin. They are both used to protect the
  skin from damage
• Fingernails and toe nails protect the tips of
  your toes and fingers
• Hair on your head protects from UV rays
• Eyelashes, Nose Hair and Ear Hair prevent dirt
  and other particles from entering the body.

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REGULATION of the HUMAN BODY
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How does the Human Body Control (Regulate) all
these body systems and make them work together?
Electrical Impulses from the Nervous System
Chemical Hormones from the Endocrine System
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The Nervous System
The nervous system is the number one
communication center of the body. The basic cell
type that carries the communications is a network
of neurons that transmit electrical impulses.
NEURON CELL
Nucleus
Axon terminals
Cell Body
Myelin Sheath
Nodes
Dendrites
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Electrical Impulses depend on the movement of
negatively charged electrons compared with the
positively charged ions across a cell membrane
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Once and impulse begins it moves along the axon
in the direction of the impulse. To pass
between neurons the impulse must be sent across a
gap known as a synapse which sends the message
from one neuron to the other.
Synapse
When the impulse reaches the end of the axon it
transfers its impulse to another cell by
releasing chemicals known as neurotransmitters
which pass the message across the synapse.
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• The nervous system is divided into two divisions
  
• The Central Nervous System (CNS) Responsible
  for relaying messages, processing and analyzing
  information.
• The Peripheral Nervous System Receives
  information from the environment and relays
  commands from the CNS to the organs and glands

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The brain is the main switching area of the
central nervous system. Cerebrum Responsible
for voluntary activities of the body
(Intelligence, learning and judgement) Cerebellum
Coordinates muscle movement Brain Stem
Consists of the pons and the medulla oblongata.
Pass message between brain and body Thalamus
Connects messages from the sense organs to the
Cerebrum Hypothalamus - Controll center for
hunger, thirst, anger and body temperature.
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The Brain
Cerebrum
Thalamus
Pineal Gland
Hypothalamus
Cerebellum
Pituitary Gland
Pons
Spinal Cord
Medulla oblongata
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The Endocrine System Sends messages throughout
the body by way of chemicals known as hormones.
Hormones travel throughout the bloodstream to
target cells which contain matching receptors.
Hormone
Receptor
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If a cell does not have a specific receptor the
hormone will not affect the cell. Responses to
hormones take longer and last longer than nervous
system messages. Hormones can take minutes,
hours or days to influence cells. Examples of
functions controlled by hormones Growth,
Metabolism, Sleep, Reaction to stress,
Reproduction.
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The Endocrine System works through a FEEDBACK
system. Glands of the Endocrine system determine
the level of a hormone in the blood and then
changes the rate of hormone production or sends
out the opposite hormone to counteract excess
amounts of hormone. Examples of Feedback
mechanisms Control of insulin/sugar levels in
blood Hypothalamus can measure water level in
blood and sends out hormones that tell the
kidneys to conserve water.
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Example of Feedback Loop
Thermostat senses temperature change and switches
off heating system
Section 35-1
Room temperature increases
Room temperature decreases
Thermostat senses temperature change and switches
on heating system
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Feedback Actions of Insulin and Glucagon
Body cells absorb glucose
Beta cells release insulin into the blood
Blood glucose level decreases
Liver converts glycogen to glucose
Blood glucose level increases
Homeostasis Normal blood glucose level
Blood glucose level increases
Blood glucose level decreases
Liver converts glycogen to glucose
Alpha cells release glucagon into blood
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Important Glands and Hormones of the Human Body
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Hypothalamus
Pineal Gland
Pituitary
Thyroid
Pancreas
Parathyroids
Ovary (female)
Thymus
Testis (male)
Adrenal Glands
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K. The Reproductive System
Functions to make new individuals by producing,
storing and releasing specialized sex cells known
as gametes. Cells from the male reproductive
system, known as sperm, must fuse with cells of
the female reproductive system, known as eggs.
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• Reproduction in both males and females is
  regulated by hormones.
• In males - Testosterone is produced by the
  testes. It is required for sperm production
  and development of male physical
  characteristics.
• In females - Estrogen and progesterone are
  female hormones produced by the ovaries.
  Estrogen is required for the development of eggs
  and female physical characteristics.
  Progesterone prepare the uterus for the arrival
  of a developing embryo.

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Neither males or females are capable of producing
active reproductive cells until puberty, which is
a period of sexual maturation. Puberty begins
when the hypothalmus signals the pituitary to
produce increased levels of hormones that affect
the sex organs (gonads). The hormones are
follicle stimulating hormone (FSH) and
luteinizing hormone (LH).
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In both the male and female reproductive system
sex cells are produced by the process of Meiosis.
Meiosis involves producing a cell with only 1
copy of each chromosome (haploid nuclei). When
the egg and sperm fuse, a cell with two copies
of each chromosome is created. Every cell in
the new individual has two copies of each
chromosome (diploid nuclei).
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The Male Reproductive System
Urinary Bladder
Vas deferens
Pubic Bone
Seminal Vesicle
Urethra
Rectum
Prostate
Penis
Epididymis
Bulbourethral gland
Testis
Scrotum
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• Sperm development
• Sperm are made from special cells in testes that
  undergo the process of meiosis.
• Once sperm mature they move through a tube known
  as the vas deferens upward from the scrotal sacs
  into the abdomen into the seminal vesicle. The
  sperm mixes with seminal fluid to form semen.
  Between 50 and 130 million sperm are present in
  one milliliter of semen. The seminal vesicle
  merges with the urethra (also connected to the
  urinary bladder)

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• During sexual excitement the nervous system of
  the male contracts the glands of the reproductive
  tract. The release of semen is controlled by the
  autonomic nervous system so it is not entirely
  voluntary. The male reproductive system is
  designed to deliver sperm into the female
  reproductive system.

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The Female Reproductive System
Section 39-3
Fallopian Tube
Ovary
Uterus
Urinary Bladder
Cervix
Rectum
Pubic Bone
Vagina
Urethra
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• The ovaries produce one mature ova or egg per
  month. Females are born with 400,000 immature
  eggs which are stored in follicles. The follicle
  assist in the maturing process of an egg from
  each ovary once a month based on a signal from
  the FSH hormone.
• When the egg matures the follicle breaks open
  releasing the egg into the fallopian tube. A
  process known as ovulation. Fertilization occurs
  in the fallopian tube if sperm is present.
• The fallopian tube connects to the uterus which
  is a cavity designed to protect and nourish a
  developing embryo.

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4. If fertilized egg enters the uterus it is
implanted into the lining of the uterus and the
embryo develops. If fertilization does not occur
the egg is discharged out of the body along with
the uterus lining through a canal known as the
vagina. Known as MENSTRUATION 5. The endocrine
system controls the cycle of events surrounding
ovulation through a feedback mechanism that can
signal the presence of a fertilized egg. While
the egg is maturing and preparing for release the
uterus is preparing for a fertilized egg by
building up the lining of the uterus. A new
lining must be created each month to prepare for
nourishing the embryo.
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The Menstrual Cycle
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Figure 11-15 Meiosis
Section 11-4
Meiosis I
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Figure 11-15 Meiosis
Section 11-4
Meiosis I
Meiosis I
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Figure 11-15 Meiosis
Section 11-4
Meiosis I
Meiosis I
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Figure 11-15 Meiosis
Section 11-4
Meiosis I
94
Figure 11-15 Meiosis
Section 11-4
Meiosis I
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Figure 11-17 Meiosis II
Section 11-4
Meiosis II
Prophase II
Metaphase II
Anaphase II
Telophase II
Meiosis I results in two haploid (N) daughter
cells, each with half the number of chromosomes
as the original.
The chromosomes line up in a similar way to the
metaphase stage of mitosis.
The sister chromatids separate and move toward
opposite ends of the cell.
Meiosis II results in four haploid (N) daughter
cells.
96
Figure 11-17 Meiosis II
Section 11-4
Meiosis II
Prophase II
Metaphase II
Anaphase II
Telophase II
Meiosis I results in two haploid (N) daughter
cells, each with half the number of chromosomes
as the original.
The chromosomes line up in a similar way to the
metaphase stage of mitosis.
The sister chromatids separate and move toward
opposite ends of the cell.
Meiosis II results in four haploid (N) daughter
cells.
97
Figure 11-17 Meiosis II
Section 11-4
Meiosis II
Prophase II
Metaphase II
Anaphase II
Telophase II
Meiosis I results in two haploid (N) daughter
cells, each with half the number of chromosomes
as the original.
The chromosomes line up in a similar way to the
metaphase stage of mitosis.
The sister chromatids separate and move toward
opposite ends of the cell.
Meiosis II results in four haploid (N) daughter
cells.
98
Figure 11-17 Meiosis II
Section 11-4
Meiosis II
Prophase II
Metaphase II
Anaphase II
Telophase II
Meiosis I results in two haploid (N) daughter
cells, each with half the number of chromosomes
as the original.
The chromosomes line up in a similar way to the
metaphase stage of mitosis.
The sister chromatids separate and move toward
opposite ends of the cell.
Meiosis II results in four haploid (N) daughter
cells.
99
Figure 11-17 Meiosis II
Section 11-4
Meiosis II
Prophase II
Metaphase II
Anaphase II
Telophase II
Meiosis I results in two haploid (N) daughter
cells, each with half the number of chromosomes
as the original.
The chromosomes line up in a similar way to the
metaphase stage of mitosis.
The sister chromatids separate and move toward
opposite ends of the cell.
Meiosis II results in four haploid (N) daughter
cells.
100
Figure 11-17 Meiosis II
Section 11-4
Meiosis II
Prophase II
Metaphase II
Anaphase II
Telophase II
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Meiosis produces specialized cells known as
gametes Each gamete must contain only half the
number of chromosomes that the parent has. The
gamete gets a mixture of chromosomes from the
parent cells.
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