The Human Respiratory Tract
1. 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
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
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)
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).
• ** 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.
• ** The end products of aerobic cellular
respiration, water and carbon dioxide
diffuse into the blood.
• Then these waste gases are released
from the lungs.
• 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
Some Respiratory
System Malfunctions
pneumonia: alveoli fill with
fluids and mucus resulting
in coughing and breathing
difficulties
asthma: allergic reaction
in which bronchiole
contractions create
breathing difficulties
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)
What happens when…
We breathe in?
-diaphragm moves downward,
creates a “low pressure” in our
thoracic cavity.
-air is forced into (we don’t 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)
The Circulatory SystemTransport
• The absorption and
circulation of
materials
throughout an
organism
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
The heart functions as a double pump
beating in unison.
1. Deoxygenated blood--relatively low in
oxygen
2. Oxygenated blood--relatively high in
oxygen
** Heartbeat is stimulated by an
electrochemical impulse.
Pacemaker - in the right atrium - initiates the
heartbeat
Pathway of a
Red Blood
Cell through
the Heart
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
A = aorta
B = pulmonary arteries
C = pulmonary veins
D = left atrium
E = valve
F = left ventricle
G = right ventricle
H = valve
I = vena cavae
J = right atrium
Some Blood Functions
Why do we need blood?????????
• ** 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.)
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.
Blood Composition
• Plasma 55% (liquid part of the blood);
Blood Cells 45%
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
** Carbon monoxide has 40X
the affinity of oxygen for
hemoglobin--breathing it may
lead to death
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
Main White Blood Cell Types
1. 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
2. Lymphocytes--produce antibodies
which clump bacterial poisons or
bacteria (antigens) (antigens--foreign
substances in the body)
3. Platelets
--smallest blood cells (fragments)
--150,000 to 300,000 per drop of blood
--needed for clotting
Clotting Process
• Involves a series of enzyme controlled
reactions resulting in the formation of
protein fibers that trap blood cells and
form a clot.
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
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
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
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
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.
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
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.
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
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