human phys test b4

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Questions and Answers

What is the first cell type in the formation of agranulocytes?

Myeloid Stem Cell

Lymphoblast

Monocyte

Hemocytoblast (correct)

Which type of stem cell gives rise to monocytes?

Mesenchymal Stem Cell

Erythroid Stem Cell

Myeloid Stem Cell (correct)

Lymphoid Stem Cell

What is the primary characteristic of leukemia?

Cancerous conditions involving leukocytes (correct)

Normal function of bone marrow

Increased red blood cell production

Increase in platelet count

What is the hormone that regulates platelet formation?

Thrombopoietin Signup and view all the answers

Which of the following is a symptom of infectious mononucleosis?

Sore throat Signup and view all the answers

What role do platelets play in the body?

Involve in blood clotting Signup and view all the answers

What is a known effect of leukopenia?

Abnormally low white blood cell count Signup and view all the answers

What type of cell fragments form thrombocytes?

Megakaryocytes Signup and view all the answers

What initiates the extrinsic pathway of coagulation?

Tissue thromboplastin release Signup and view all the answers

Which phase of coagulation involves the conversion of prothrombin into thrombin?

Phase II Signup and view all the answers

What is the primary role of fibrin threads in the clotting process?

Creating a gel-like plasma matrix Signup and view all the answers

Which proteins do platelets contain that contribute to clot retraction?

Actin and myosin Signup and view all the answers

What enzyme is responsible for digesting blood clots during the fibrinolysis process?

Plasmin Signup and view all the answers

How long after clot formation does fibrinolysis typically begin?

2 days Signup and view all the answers

What is the main function of the fibrin threads during clot formation?

To provide a surface for platelet attachment Signup and view all the answers

Which mechanism helps to maintain homeostasis and prevent excessive clotting?

Plasminogen activation Signup and view all the answers

What is the first stage in the development of blood cells from hemocytoblasts?

Myeloid stem cells Signup and view all the answers

Which statement is true about normoblasts?

Normoblasts lose all cellular organelles. Signup and view all the answers

What role do reticulocytes play in the bloodstream?

They transport oxygen and carbon dioxide. Signup and view all the answers

What effect does excess oxygen or too many erythrocytes have on erythropoietin production?

It suppresses erythropoietin production. Signup and view all the answers

How long does it take for reticulocytes to mature into erythrocytes?

Two days Signup and view all the answers

What percentage of all erythrocytes do reticulocytes account for in a healthy human?

2-3% Signup and view all the answers

What can cause hypoxia, leading to an increase in erythropoietin production?

Reduced number of erythrocytes Signup and view all the answers

What is the typical rate of erythrocyte production in healthy individuals?

2 million per second Signup and view all the answers

What is the primary function of the conducting zone in the respiratory system?

It serves as a conduit for air to reach the respiratory zone. Signup and view all the answers

Which of the following structures does NOT belong to the conducting zone?

Bronchioles Signup and view all the answers

What is the primary role of goblet cells in the respiratory mucosa?

They produce mucus to trap dust and microbes. Signup and view all the answers

How does the respiratory mucosa help in preparing air for the lungs?

By warming and humidifying the air. Signup and view all the answers

What is the relationship between flow rate and resistance in the cardiovascular system?

Increased resistance leads to decreased flow rate. Signup and view all the answers

Which bones contain the paranasal sinuses that aid in warming and moistening incoming air?

Maxillary and sphenoid bones Signup and view all the answers

What drives blood flow from one region to another in the cardiovascular system?

Pressure gradient. Signup and view all the answers

What occurs during rhinitis?

Inflammation of the nasal mucosa. Signup and view all the answers

What is the function of capillaries located beneath the respiratory mucosa?

To warm and humidify the incoming air. Signup and view all the answers

What defines the Mean Arterial Pressure (MAP)?

The average pressure in the aorta during the cardiac cycle. Signup and view all the answers

What is epistaxis and what commonly causes it?

Nosebleeds; increased blood flow to the nasal cavity. Signup and view all the answers

If the Central Venous Pressure (CVP) is 5 mmHg and the Mean Arterial Pressure (MAP) is 85 mmHg, what is the pressure gradient driving blood flow through the systemic circulation?

80 mmHg. Signup and view all the answers

What role does the heart play in the cardiovascular system?

It generates the pressure that drives blood flow. Signup and view all the answers

What happens to blood flow if the pressure gradient driving it is low?

Resistance must also be low. Signup and view all the answers

Which statement accurately describes pressure in the cardiovascular system?

Pressure gradient is defined as the difference in pressure between two locations. Signup and view all the answers

What is the likely effect of increased resistance on blood flow rate?

Blood flow rate decreases. Signup and view all the answers

What happens when the net filtration pressure (NFP) is positive?

Filtration occurs. Signup and view all the answers

Which of the following best describes the primary function of the valves in veins?

To prevent backflow of blood. Signup and view all the answers

What is true about the walls of veins compared to arteries?

Veins have walls that are structured similarly to arteries. Signup and view all the answers

Which condition is least likely to affect fluid levels in tissues?

Skin rash Signup and view all the answers

What does high compliance in veins mean?

Veins can easily stretch to accommodate blood volume. Signup and view all the answers

Which pressure is primarily related to fluid outside of a capillary?

Interstitial fluid hydrostatic pressure Signup and view all the answers

What do veins primarily serve as within the circulatory system?

Volume reservoirs Signup and view all the answers

At which end of a capillary does absorption occur?

At the venule end. Signup and view all the answers

Study Notes

Blood Vessels, Blood Pressure and Blood Flow

Blood flow rate is determined by the pressure gradient across the vessel and inversely related to resistance.
Flow = Pressure gradient/Resistance
Increased resistance decreases flow rate.
Decreased resistance increases flow rate.
Pressure gradient drives blood flow from higher to lower pressure.
The heart is the primary pump, creating pressure gradients.
Mean Arterial Pressure (MAP) — average pressure in the aorta (approximately 85 mm Hg).
Central Venous Pressure (CVP) — pressure in large veins returning to the heart (approximately 2-8 mmHg).

Pressure Gradient Differences

Pressure gradient drives blood flow in the systemic circulation.
The pressure gradient is equated to the Mean Arterial Pressure (MAP).
Resistance in the cardiovascular system must be low to have a sufficient pressure gradient.

Resistance in the Cardiovascular System

Resistance refers to any condition that reduces blood flow.
Vessel radius; a decrease increases resistance (vasoconstriction), and an increase decreases resistance (vasodilation).
Vessel length.
Blood viscosity.
The primary determinant of blood velocity is the total cross-sectional area of the vessel.

Overview of Blood Vessels

Blood vessels are classified by their direction (away from or toward the heart) and size.
Arteries and arterioles carry oxygenated blood away from the heart.
Venules and veins carry deoxygenated blood to the heart.

Arteries

Arterial walls have three layers (tunics):
- Tunica interna (intima).
- Tunica media.
- Tunica externa (adventitia).
Tunica media is largely composed of smooth muscle and elastic connective tissue.

Capillaries

Capillaries are the smallest blood vessels (1µm in diameter).
They are thin walled, making them highly permeable to substances.
There are three types of capillaries: continuous, fenestrated, and sinusoidal.
The density of capillaries in a tissue is related to its metabolic activity.

Veins

Veins have a larger diameter than arteries.
The walls of veins are thinner than artery walls.
Veins typically contain valves to prevent backflow of blood.
Veins serve as volume reservoirs, holding more blood than arteries.

Blood Pressure and Blood Flow to Organs

Blood flow to organs is regulated locally based on their metabolic needs.
Intrinsic control regulates blood flow based on metabolic activity. This is done using locally secreted chemical messengers.
Active hyperemia involves increased blood flow to an organ in response to increased metabolic activity.
Active hyperemia causes vasodilation-increasing blood flow.

Regulation of Blood Flow and Pressure

Intrinsic control of blood flow:
- Blood flow to an organ is locally regulated by chemical messengers, such as nitric oxide, adenosine and prostacyclin.
Extrinsic control:
- Blood flow is regulated by the autonomic nervous system and hormones.
- Epinephrine/norepinephrine constricts peripheral arterioles.
- Epinephrine/norepinephrine dilates coronary blood vessels.
- Vasopressin constricts many blood vessels.
- Angiotensin II constricts many blood vessels.

Blood Composition

Plasma (liquid component):
Primarily water (over 90%).
Proteins (e.g., albumin, globulins)
Other substances (e.g., electrolytes, nutrients).
Formed elements (cells):
Erythrocytes (red blood cells): Transport oxygen.
Leukocytes (white blood cells): Defend against infection.
Platelets: Involved in clotting.

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