Human Circulation and Respiratory System

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Human Circulation and Respiratory System

• How the good stuff gets to all of the right places

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Circulatory System Functions

• Carry O2 to cells and CO2 away from cells
• Deliver nutrients through body (after absorption
  in small intestine)
• Carry liquid wastes away from cells (H2O, salt,
  urea)
• Help in fighting infections
• Temperature regulation

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Three circuits

• Pulmonary
• Blood goes from heart to lungs to pick up oxygen
  and release carbon dioxide
• Systemic
• Blood pumped out of heart to the rest of the body
• Sound of heart (lub/dub) made by valves closing
• Coronary
• Heart muscle itself supplied with oxygen,
  nutrients, etc.

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Blood flow through the body

• Blood vessels
• Arteries--take oxygenated blood away from the
  heart
• Thick/muscular walls
• Do not contain valves
• High Pressure

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Blood flow through the body

• Capillaries
• Gases diffuse across very thin wall of small
  vessels
• Nutrients and oxygen leave the blood and go into
  the body tissue

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Blood flow through the body

• Blood vessels
• Veins--take deoxygenated blood back to the heart
• Thin walls
• Have one-way valves
• Low Pressure

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Blood Flow through Heart
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Blood flow through the heart

• Into vena cava
• Into right atrium
• Dow to right ventricle
• Out pulmonary artery to lungs
• Gets O2 and dumps CO2
• Back to heart through pulmonary vein
• Into left atrium
• Down to left ventricle
• Out aorta to body

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Blood flow through rest of body
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Components of Blood

• Blood contents
• Plasma
• 90 Water
• Nutrients, Proteins
• Wastes, Dissolved CO2
• Cells
• Red blood cells (erythrocytes)
• Made in bone marrow
• 25 trillion of them (1000 RBC1 WBC)
• Carry O2 and CO2
• White blood cells (leukocytes)
• fight infection
• About 0.1 of all blood cells
• Platelets--involved in the formation of clots
  (along with fibrinogen (protein in blood) and
  blood cells)

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Removal of wastes

• Blood takes CO2 back to lungs
• Delivers salts, water, and nitrogenous wastes
  (urea) to the kidneys for excretion
• Urea
• Main nitrogenous waste of body
• Produced in liver (from ammonia--NH3)
• Removed by kidneys

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Health of the circulatory system

• Arteriosclerosis-- hardening of the arteries
• Hypertension--high blood pressure
• Can be caused by a number of things
• Diseases affected by lifestyle (eating, smoking,
  exercise, etc.) and by genetics

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Blood disorders

• Anemia--Too little iron in blood, resulting in
  less ability to carry oxygen
• Sickle-cell anemia--misshaped RBCs
• RBCs get clogged in small capillaries
• Less ability to carry oxygen
• Leukemia--cancer of blood
• Bone marrow produces and releases immature stem
  cells--not able to fight infection
• May also be prone to anemia and inability to clot
  blood

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Function of Respiratory System

• Main job of respiratory system
• Get oxygen into the body and waste gases out of
  the body
• Also to transport gases to and from the
  circulatory system

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Requirements of gas exchange

• Moist environment
• O2 and CO2 must be dissolved to diffuse
• Lungs, gills, moist surface (slime) help
• Surface area--large area allows for more
  diffusion
• Cleaned and filtered
• Warmed

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Movement of air into body

• Nose--external opening to allow entry
• Air is filtered, cleaned, warmed, moistened
• Enters a series of tubes
• Protected by cartilage to keep tubes firm/open
• Mucus--traps foreign particles
• Cilia-- sweep foreign material away from lungs
  to be swallowed (or spit/coughed)

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System of tubes

• Pharynx--branches into esophagus and larynx
• Larynx--voice box, protected by epiglottis
• Trachea--main passageway to lungs
• Bronchi--two branches off the trachea that lead
  to lungs
• Bronchioles--smaller branches of the bronchi that
  lead to alveoli
• Alveoli--small air sacs at end of bronchioles
• Great deal of surface area
• Actual site of gas exchange

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Structure of alveoli
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Diffusion of gases

• O2 concentration is higher in alveoli than blood
  oxygen diffuses into blood
• Remember High Conc. -gt Low Conc.
• At body cells O2 concentration is higher in
  blood oxygen diffuses out of blood

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Oxygen Transport

• O2 diffuses from alveoli to the pulmonary
  capillaries.
• O2-rich blood travels to heart and pumped to the
  body
• O2 diffuses into cells. In tissues O2 levels are
  lower triggers Hb to release O2
• In tissues, CO2 makes blood more acidic and
  causes Hb to change shape.
• CO2 diffuses from cells to blood. Travels to
  heart in form of Bicarbonate ions (HCO3-)
• Heart pumps blood to lungs where CO2 is released
  in in gaseous form and then expelled.

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Health of Respiratory System

• Colds
• Caused by virus, Attacks nasal mucous membranes
• Causes cells to produce histamine--eyes to tear,
  more mucus, labored breathing
• Pneumonia
• Caused by virus or bacteria, Inflammation of
  alveoli
• Weak and tired due to less oxygen exchange
• Bronchitis
• Caused by bacteria or virus (cold or flu),
  Inflammation of bronchi
• Cough to clear excess mucus

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Health of Respiratory system

• Asthma
• May be allergic, or response to stress, exercise,
  etc.
• Narrowed breathing passages (bronchi)
• Treated with drugs that relax air passages

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Smoking

• Cigarette smoke contains
• Cyanide
• Cancer-causing tar
• Carbon monoxide
• Radioactive materials
• Nicotine
• Addictive
• Increased heart rate and narrowed blood vessels

• Cancer and smoking
• Lung cancer from smoking
• Mouth and throat cancers from chewing tobacco
• Other problems
• Chronic coughing--due to paralyzed/destroyed
  cilia
• Emphysema--Labored breathing due to inelasticity
  of alveoli

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Cancer and emphysema