The Circulatory System

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The Circulatory System
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The Human Respiratory Tract
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• nostrils opening to the nasal passages
• 2. nasal passages lined with a mucus membrane
  bearing cilia (warms, moistens, and filters
  incoming air)
• 3. pharynx (throat)--cavity in back of mouth

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• 4. glottis windpipe or trachea opening
• epiglottis--muscular flap covering the
  glottis--prevents food from entering the windpipe
  
• 5. larynx (voice box) upper part of the windpipe
  containing sound producing vocal cords
• 6. trachea (windpipe)--about 4 inches long 1
  inch in diameter --supported by rings of
  cartilage --lined with a ciliated mucus membrane
  which filters incoming air

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• 7. bronchi two main branches of trachea which
  enter lungs --lined with cartilage and ciliated
• 8. bronchioles smallest air tubes which end at
  the alveoli or air sacs --cartilage ring support
  "fades out from this point on
• 9. alveoli (air sacs) site of respiratory gas
  exchange by diffusion --resemble bunches of
  grapes --moist surface aids exchange--each
  alveolus is surrounded by capillaries gas
  exchange occurs with them (oxygen in--carbon
  dioxide out)

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Purpose and Function of the System

• The purpose of getting in oxygen is to get it
  through our bloodstream to the cells of our body.
  
• At our cells it combines with glucose food to
  form usable ATP energy (cell respiration).

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• The capillaries which surround the alveoli are
  involved in gas exchange between the blood and
  the alveoli.
• In the blood, oxygen is carried by the red blood
  cell as oxyhemoglobin.
• Oxygen, which is loosely bound to the hemoglobin,
  diffuses into the cells where it is used during
  aerobic cellular respiration.

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• The end products of aerobic cellular
  respiration, water and carbon dioxide diffuse
  into the blood.
• Then these waste gases are released from the
  lungs.

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• diaphragm sheet of muscle separating the
  thoracic (chest) cavity from the abdominal cavity
  
• Breathing - the mechanical part of respiration
  ... involves both the diaphragm and rib cage
  muscles

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Some Respiratory System Malfunctions
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pneumonia alveoli fill with fluids and mucus
resulting in coughing and breathing difficulties
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asthma allergic reaction in which bronchiole
contractions create breathing difficulties
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emphysema air sacs lose their elasticity and
breakdown resulting in a loss of respiratory
surface in the lungs --shortness of breath is the
chief symptom (smoking frequently leads to this
disorder)
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What happens when We breathe in? -diaphragm
moves downward, creates a low pressure in our
thoracic cavity. -air is forced into (we dont
suck it into) our lungs, filling any available
empty space. We breathe out? -diaphragm pushes
upwards, creating a high pressure in our thoracic
cavity. -air is forced out through our nose and
mouth, leaving a low that can be refilled
(hopefully immediately)
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The Circulatory System-Transport

• The absorption and circulation of materials
  throughout an organism

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The Human (Mammalian) Heart Structure

• 1. septum muscular central wall dividing the
  mammalian heart into two halves
• 2. atria thin walled upper heart chambers which
  receive blood pump blood to the ventricles
• 3. Ventricles muscular thick walled chambers
  which pump blood from the heart -- the lower
  chambers
• 4. Valves - prevent the backward flow of blood in
  the heart

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• The heart functions as a double pump beating in
  unison.
• 1. Deoxygenated blood--relatively low in oxygen
• Oxygenated blood--relatively high in oxygen
• Heartbeat is stimulated by an electrochemical
  impulse.
• Pacemaker - in the right atrium - initiates the
  heartbeat

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Pathway of a Red Blood Cell through the Heart
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• 1. Inferior superior vena cava
• 2. Right atrium
• 3. valve
• 4. Right ventricle
• 5. valve
• 6. Pulmonary arteries
• (BLOOD TO THE LUNGS
• GAS EXCHANGE)
• 7. Pulmonary veins
• 8. Left Atrium
• 9. valve
• 10. Left ventricle
• 11. valve
• 12. Aorta

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• A aorta F left ventricle
• B pulmonary arteries G right ventricle
• C pulmonary veins H valve
• D left atrium I vena cavae
• E valve J right atrium

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Some Blood Functions

• Why do we need blood?????????

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• In general, the blood is a fluid tissue
  helping to maintain homeostasis for all cells in
  the body.
• Transport of needed substances to body cells.
  (oxygen, amino acids, glucose, fatty acids,
  glycerol, salts, etc.)

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• 2. Transport of wastes from cells. (urea, water,
  carbon dioxide in the form of the bicarbonate
  ion)
• 3. Helps to maintain a constant body temperature.
  
• 4. Aids the body in fighting disease.

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Blood Composition

• Plasma 55 (liquid part of the blood) Blood
  Cells 45

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BLOOD CELL TYPES

• Red Blood Cells
• most numerous
• biconcave disc shaped
• smaller than white blood cells, larger than
  platelets
• no nucleus when mature
• produced in the red marrow of long bones
• destroyed in the liver and spleen
• contain the iron protein compound HEMOGLOBIN
  whose chief function is to combine with oxygen
  and carry it to the cells

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Carbon monoxide has 40X the affinity of oxygen
for hemoglobin--breathing it may lead to death
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• White Blood cells
• --largest blood cells--several different types
• --about 8,000 per drop of blood
• --most are formed in the bone marrow or in the
  lymph tissue
• --most protect the body against diseases by
  forming antibodies or engulfing bacteria

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Main White Blood Cell Types

• Phagocytes-- engulf bacteria and viruses by
  phagocytosis
• --able to leave the bloodstream
• and move between the cells of
• the body by squeezing through
• the capillary walls

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• 2. Lymphocytes--produce antibodies which clump
  bacterial poisons or bacteria (antigens)
  (antigens--foreign substances in the body)

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• 3. Platelets
• --smallest blood cells (fragments)
• --150,000 to 300,000 per drop of blood
• --needed for clotting

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Clotting Process

• Involves a series of enzyme controlled reactions
  resulting in the formation of protein fibers that
  trap blood cells and form a clot.

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Blood Vessels

• 1. Arteries
• --carry blood away from the heart
• --usually spurt blood when cut
• --all except the pulmonary artery carry
  oxygenated blood
• --thick walled and elastic
• pulse expansion and contraction of the artery
  walls in response to the heartbeat

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• Veins
• --carry blood toward the heart
• --contain valves
• --closer to the body surface than the arteries
• --all except the pulmonary vein carry
  deoxygenated blood
• --thinner, less muscular and elastic than
  arteries
• --depend upon muscle and diaphragm movements for
  blood flow

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• Capillaries
• --most numerous vessels
• --connect arteries to veins
• --microscopic, one cell thick walls
• --site of much exchange between the blood and the
  intracellular fluid (lymph) by diffusion

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• Lymph vessels
• -have walls one cell thick
• -present around all body cells
• -Lymph composition is similar to that of blood
  except for the absence of RBC and some plasma
  proteins.
• -chief site of material exchange with the
  tissues

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• Major lymph vessels have lymph nodes which
  contain phagocytic white blood cells which filter
  bacteria and dead cells from the lymph.
• X lymph nodes
• Valves are present in some lymph vessels--aiding
  in the movement of the lymph.
• Respiratory movements also aid lymph flow.

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Malfunctions and disorders of the heart and blood
vessels

• Hypertension (High Blood Pressure)
• --caused by a narrowing of the arterioles
  resulting in an increased resistance to the flow
  of blood--increases
• the strain on the heart

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• Causes implicated
• 1. excess sodium intake
• 2. stress
• 3. cigarettes (nicotine)
• 4. saturated fats
• 5. alcohol caffeine
• 6. obesity
• 7. heredity aging
• No cure--may be treated by medication diet.
• "Silent killer"--millions don't know they have it

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Angina pectoris

• --pain in the chest which radiates into the left
  shoulder and arm
• --occurs especially when physical exertion
  results in a lack of oxygen supply to the heart
  muscle
• --caused by a reduction of blood supply due to
  partial blockage(s) of coronary arteries

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Coronary thrombosis - heart attack

• --caused by a blood clot in a coronary artery
  that stops circulation to part of the heart
  muscle
• --attack is fatal if much heart muscle is involved