Assignment 3 94%
Weight: 5%
Minimum Pass Grade: 50%
Each question is worth 10 marks.
1. Fill in the words or phrases that best complete each sentence. Be as specific as
possible.
a. Erythrocytes contain the enzyme carbonic anhydrase which catalyzes the
conversion of metabolically produced CO2 and water into H+ and HCO3-.
b. Most old erythrocytes are removed from circulation and destroyed by cells
called fixed phagocytic macrophages as they rupture passing through the
narrow capillaries of the organ called the spleen, liver and red blood marrow.
c. Undifferentiated cells called pluripotent stem cells reside in the bone marrow,
where they continuously divide and differentiate to give rise to each of the
types of blood cells.
d. The process of leukocytes squeezing through the capillary pores to exit the
vasculature is known as emigration. Once they leave the bloodstream to fight
a pathological condition, they never return.
e. The genetically-determined glycoprotein and glycolipid antigens found on the
surface of an erythrocyte are called agglutinogens, and a person with
agglutinins that react with type A and blood type B has type O blood.
f. During embryonic development, ninety-nine percent of the cardiac fibers are
specialized for the function called contraction whereas the remainder is
specialized for autorhythmic electrical activity.
g. The action potential delay at the atrioventricular node ensures that atrial
excitation and contraction are complete before ventricular excitation and
contraction commence.
Assignment 3 :: Biology 235: Human Anatomy and Physiology 1
, h. The end-systolic volume is the volume of blood in the ventricle after ejection
has been completed. An increase of this volume occurs when the stroke
volume is decreased.
i. The three cations, K+, Ca2+, and Na+ have an important effect of heart function.
Increased blood levels of Na+ blocks Ca2+ inflow and results in a decrease in
the force of contraction, while an excess of K+ blocks the generation of action
potentials.
j. An increase in parasympathetic activity has the following effect on stroke
volume: no effect. An increase in parasympathetic activity weakens atrial
contractility.10
2. A patient has the misfortune to have both diabetes insipidus and Addison’s
disease. How will those conditions affect the patient’s ability to regulate blood
pressure?
Diabetes insipidus is a disorder caused by the hyposecretion of antidiuretic
hormone (ADH) or defective ADH receptors. ADH is a hormone produced by
the hypothalamus and released from the posterior pituitary in response to
dehydration or decreased blood volume. This hormone works to decrease urine
production by promoting water movement from the lumen of the kidneys tubules
into the bloodstream, thereby returning more water to the blood and subsequently
decreasing urine volume while increasing blood volume and blood pressure.
ADH also causes an increase in blood pressure by decreasing water lost through
sweating and causes constriction of the arterioles. Because the patient has
diabetes insipidus, a disorder characterized by low levels or absence of ADH,
when their body is experiencing low blood volume or blood pressure, they will
be unable to reestablish homeostasis by promoting water reabsorption from the
lumen of the kidney tubules or vasoconstriction of their arterioles. They will
instead experience large volumes of urine, low blood pressure, dehydration, and
increased thirst.
Assignment 3 :: Biology 235: Human Anatomy and Physiology 2
Weight: 5%
Minimum Pass Grade: 50%
Each question is worth 10 marks.
1. Fill in the words or phrases that best complete each sentence. Be as specific as
possible.
a. Erythrocytes contain the enzyme carbonic anhydrase which catalyzes the
conversion of metabolically produced CO2 and water into H+ and HCO3-.
b. Most old erythrocytes are removed from circulation and destroyed by cells
called fixed phagocytic macrophages as they rupture passing through the
narrow capillaries of the organ called the spleen, liver and red blood marrow.
c. Undifferentiated cells called pluripotent stem cells reside in the bone marrow,
where they continuously divide and differentiate to give rise to each of the
types of blood cells.
d. The process of leukocytes squeezing through the capillary pores to exit the
vasculature is known as emigration. Once they leave the bloodstream to fight
a pathological condition, they never return.
e. The genetically-determined glycoprotein and glycolipid antigens found on the
surface of an erythrocyte are called agglutinogens, and a person with
agglutinins that react with type A and blood type B has type O blood.
f. During embryonic development, ninety-nine percent of the cardiac fibers are
specialized for the function called contraction whereas the remainder is
specialized for autorhythmic electrical activity.
g. The action potential delay at the atrioventricular node ensures that atrial
excitation and contraction are complete before ventricular excitation and
contraction commence.
Assignment 3 :: Biology 235: Human Anatomy and Physiology 1
, h. The end-systolic volume is the volume of blood in the ventricle after ejection
has been completed. An increase of this volume occurs when the stroke
volume is decreased.
i. The three cations, K+, Ca2+, and Na+ have an important effect of heart function.
Increased blood levels of Na+ blocks Ca2+ inflow and results in a decrease in
the force of contraction, while an excess of K+ blocks the generation of action
potentials.
j. An increase in parasympathetic activity has the following effect on stroke
volume: no effect. An increase in parasympathetic activity weakens atrial
contractility.10
2. A patient has the misfortune to have both diabetes insipidus and Addison’s
disease. How will those conditions affect the patient’s ability to regulate blood
pressure?
Diabetes insipidus is a disorder caused by the hyposecretion of antidiuretic
hormone (ADH) or defective ADH receptors. ADH is a hormone produced by
the hypothalamus and released from the posterior pituitary in response to
dehydration or decreased blood volume. This hormone works to decrease urine
production by promoting water movement from the lumen of the kidneys tubules
into the bloodstream, thereby returning more water to the blood and subsequently
decreasing urine volume while increasing blood volume and blood pressure.
ADH also causes an increase in blood pressure by decreasing water lost through
sweating and causes constriction of the arterioles. Because the patient has
diabetes insipidus, a disorder characterized by low levels or absence of ADH,
when their body is experiencing low blood volume or blood pressure, they will
be unable to reestablish homeostasis by promoting water reabsorption from the
lumen of the kidney tubules or vasoconstriction of their arterioles. They will
instead experience large volumes of urine, low blood pressure, dehydration, and
increased thirst.
Assignment 3 :: Biology 235: Human Anatomy and Physiology 2
