Human Circulatory System Overview

Questions and Answers

What is complement fixation?

Each complement pathway involves a cascade in which complement proteins are activated in an orderly sequence, leading to cell lysis, phagocytosis, and inflammation.

For the activation of complement proteins, what is the difference between classical and alternative pathways?

The classical pathway is part of adaptive immunity and depends on the binding of antibodies to invading organisms, while the alternative pathway is part of innate immunity and is triggered by interactions among factors B, D, P and polysaccharide molecules on microorganisms.

Describe interferons.

Interferons leave infected cells, enter neighboring cells, stimulate those cells to produce proteins to prevent viral replication, and activate macrophages and natural killer cells.

Describe the inflammatory response.

Chemical mediators cause vasodilation and increased vascular permeability, attracting phagocytes until the cause of inflammation is destroyed, leading to local symptoms like redness, heat, swelling, pain, and loss of function. Signup and view all the answers

What are the two types of adaptive immunity?

Antibody-mediated immunity and cell-mediated immunity. Signup and view all the answers

What is an antigen, and what is the difference between B and T cells?

Antigens are large molecules that stimulate an adaptive immune response; B cells are responsible for antibody-mediated immunity, while T cells are involved with cell-mediated immunity. Signup and view all the answers

What is the difference between MHC class I and MHC class II molecules?

MHC class I molecules display antigens on nucleated cells leading to their destruction, while MHC class II molecules display antigens on antigen-presenting cells, activating immune cells. Signup and view all the answers

Which of the following is NOT a function of the blood vessels which help to maintain homeostasis? (Select all that apply)

Generate blood pressure Signup and view all the answers

Which blood vessels allow the exchange of gases and nutrients between the blood and tissues?

Capillaries Signup and view all the answers

The wall of the blood vessel is composed of three layers. Which of the following is NOT a layer of a blood vessel wall?

Tunica fibrosa Signup and view all the answers

What is the name of the blood vessel layer that contains smooth muscle fibers?

Tunica media Signup and view all the answers

Which arteries are the distributing arteries?

Muscular arteries Signup and view all the answers

What is the name of the blood vessel that directly connects an arteriole to a venule?

Thoroughfare channel Signup and view all the answers

What is the flow of blood as blood moves from the heart to the tissues back to the heart?

Elastic arteries, Muscular arteries, Arterioles, Capillaries, Venules, Veins Signup and view all the answers

What is the equation that describes mean arterial blood pressure (MAP)?

MAP = CO X PR Signup and view all the answers

What is it called when the sympathetic stimulation keeps the arteries in a constant state of partial constriction?

Vasomotor tone Signup and view all the answers

Which pair of processes is responsible for the exchange of fluids across the walls of capillaries?

Diffusion and osmosis Signup and view all the answers

Which of the following local control mechanisms would increase blood flow to the tissues? (Select all that apply)

Arterioles vasodilate and precapillary sphincters relax Signup and view all the answers

What sensory receptors detect changes in arterial stretch?

Baroreceptors Signup and view all the answers

What is the effect of epinephrine released from the adrenal medulla?

Vasodilation in the skeletal and cardiac muscles and vasoconstriction in skin and kidneys Signup and view all the answers

Which of the following is NOT a chemical that is detected by chemoreceptors that affects blood pressure? (Select all that apply)

Sodium Signup and view all the answers

A drop in oxygen results in an

Increased blood pressure Signup and view all the answers

All of the following are effects of the release of renin by the kidney because of low blood pressure EXCEPT: (Select all that apply)

Release of TSH Signup and view all the answers

What are the effects of aldosterone?

Conserving sodium ion and water by kidneys, increased blood volume, decreased urine volume Signup and view all the answers

What mechanism causes a decrease in blood pressure?

Atrial natriuretic mechanism Signup and view all the answers

Which of the following is NOT a part of the lymphatic system? (Select all that apply)

Pancreas Signup and view all the answers

What are the lymphatic vessels in the small intestine that absorb fat?

Lacteals Signup and view all the answers

What is the primary cell in lymphatic organs?

Lymphocyte Signup and view all the answers

What are the lymphatic nodules that are found in the small intestine and appendix?

Peyer's patches Signup and view all the answers

Which of the following is a bean-shaped structure that is distributed along lymph vessels?

Lymph node Signup and view all the answers

What two types of immunity does the body have?

Innate and adaptive Signup and view all the answers

What is the nonspecific lymphocyte that kills tumor cells and virus-infected cells?

Natural killer cells Signup and view all the answers

Which of the following is an effect of the inflammatory response in damaged or infected tissue? (Select all that apply)

All of the above Signup and view all the answers

What molecule presents antigens to immune cells?

Major histocompatibility complex class II molecules Signup and view all the answers

Describe the structure of an antibody.

Two heavy chains and two light chains Signup and view all the answers

What part of an antibody combines with an antigen?

Variable region Signup and view all the answers

Which of the following immunities is caused by antibodies being passed from the mother's blood across the placenta into the fetus' blood?

Passive natural immunity Signup and view all the answers

What is the name of the age-related change in arteries caused by the deposition of materials in the walls of arteries to form plaques?

Atherosclerosis Signup and view all the answers

What is the flow of blood from the heart through the systemic circulation?

Aorta, arteries, arterioles, capillaries, venules, veins Signup and view all the answers

What is the blood pressure that occurs when the ventricles are contracting?

Systolic pressure Signup and view all the answers

What would cause a decrease in blood flow?

Increased viscosity of blood Signup and view all the answers

Which of the following hormones is NOT produced by the anterior pituitary gland? (Select all that apply)

Oxytocin Signup and view all the answers

When the ventricles contract, what happens?

The atrioventricular valves close and the semilunar valves open Signup and view all the answers

What are the functions of the peripheral circulatory system?

<ol> <li>Carries blood 2. Exchanges nutrients, waste products, and gases with tissues 3. Transports substances 4. Helps regulate blood pressure 5. Directs blood flow to tissues</li> </ol> Signup and view all the answers

What are the three major blood vessels?

Veins, arteries, and capillaries Signup and view all the answers

What is the difference between an artery and a vein?

Arteries carry blood away from the heart toward capillaries, where exchange between the blood and interstitial fluid occurs. Veins carry blood from the capillaries toward the heart. Signup and view all the answers

Describe the tissue layers of blood vessels.

Inner: tunica intima, Middle: tunica media, Outer: tunica adventitia Signup and view all the answers

What are the three types of arteries?

Elastic, muscular, arterioles Signup and view all the answers

Describe capillaries.

Capillaries consist only of endothelium and have a networked structure. They allow for the exchange of gases and nutrients. Signup and view all the answers

What is arteriosclerosis?

Results from a loss of elasticity in the aorta, large arteries, and coronary arteries. Signup and view all the answers

What is vasomotor tone?

A state of partial contraction of blood vessels. Signup and view all the answers

What is pulse pressure and vascular compliance?

Pulse pressure is the difference between systolic and diastolic pressures. Vascular compliance is a measure of volume change in blood vessels produced by pressure change. Signup and view all the answers

How does gravity affect blood pressure?

In a standing person, hydrostatic pressure increases blood pressure below the heart and decreases pressure above the heart. Signup and view all the answers

How is blood flow controlled?

Through local control and nervous/hormonal control mechanisms. Signup and view all the answers

Describe short-term regulation of blood pressure.

Baroreceptor reflexes and chemoreceptor reflexes regulate blood pressure by responding to changes in arterial stretch and blood composition. Signup and view all the answers

Describe long-term blood pressure regulation.

Through mechanisms such as renin-angiotensin-aldosterone, vasopressin, and atrial natriuretic hormone. Signup and view all the answers

Describe cardiovascular regulation during exercise.

The body increases cardiac output and adjusts blood flow based on metabolic needs while maintaining blood pressure. Signup and view all the answers

Describe cardiovascular regulation during circulatory shock.

Reflexes increase blood pressure and blood volume through various compensatory mechanisms. Signup and view all the answers

Describe the lymphatic system.

Consists of lymphatic vessels and lymphoid tissues/organs that return interstitial fluid to the blood and play roles in immune response. Signup and view all the answers

Describe lymphatic vessels.

One-way system that transports lymph toward the heart, including lymphatic capillaries, vessels, and ducts. Signup and view all the answers

How does lymph move?

Lymph flows through contraction of lymphatic smooth muscle, skeletal muscle action, and thoracic pressure changes. Signup and view all the answers

Describe the two ducts of the lymphatic system.

Right lymphatic duct drains the right upper limb and side of the head; thoracic duct drains the rest of the body. Signup and view all the answers

Describe lymphatic tissue.

Reticular connective tissue containing lymphocytes, which can be encapsulated (nodes, spleen) or non-encapsulated (nodules). Signup and view all the answers

What are Peyer's patches?

Isolated clusters of lymphoid tissue in the small intestine that help prevent bacterial breach of intestinal walls. Signup and view all the answers

Describe the tonsils.

Simplest lymphoid organs forming a ring around the pharynx, trapping and destroying bacteria. Signup and view all the answers

Describe the lymph nodes.

Principal lymphoid organs that filter lymph and activate the immune response. Signup and view all the answers

Describe the spleen.

Located in the left upper abdomen, involved in immune function and filtration of blood. Signup and view all the answers

Describe the thymus.

A bilobed organ that matures T lymphocytes and secretes thymosin hormones. Signup and view all the answers

What are the types of immunity?

Adaptive immunity and innate immunity. Signup and view all the answers

What types of immunity fall under innate immunity?

Non-specific defenses like physical barriers, phagocytosis, and inflammatory responses. Signup and view all the answers

Study Notes

Blood Vessel Functions

Blood vessels carry blood, generating pressure, and facilitate nutrient, waste, and gas exchange.
The generation of blood pressure is not a function of blood vessels.

Blood Vessel Structures

Capillaries are the primary vessels for gas and nutrient exchange.
Blood vessel walls consist of three layers: tunica intima, tunica media, and tunica adventitia; tunica fibrosa is not a layer.

Blood Flow Pathways

Blood flows from the heart through elastic arteries, muscular arteries, arterioles, capillaries, venules, and veins.
A thoroughfare channel connects an arteriole to a venule directly.

Blood Pressure Dynamics

Mean arterial pressure (MAP) is calculated as MAP = cardiac output (CO) x peripheral resistance (PR).
Vasomotor tone describes sympathetic stimulation causing partial constriction of arteries.

Fluid Exchange at Capillaries

Diffusion and osmosis are key processes allowing fluid exchange across capillary walls.

Local Control Mechanisms

Arterioles vasodilating and precapillary sphincters relaxing increase blood flow to tissues.

Receptors and Responses

Baroreceptors detect arterial stretch and regulate blood pressure.
Epinephrine induces vasodilation in muscles and vasoconstriction in non-essential areas.

Renin-Angiotensin System

Renin release leads to the conversion of angiotensinogen to angiotensin I, influencing blood pressure regulation and fluid balance.
Aldosterone conserves sodium and water, increasing blood volume.

Lymphatic System Overview

The lymphatic system consists of lymph vessels and lymphoid organs, returning fluid to the bloodstream.
Lacteals in the small intestine absorb fats, while lymph nodes filter lymph and activate immune responses.

Immunity Types

The immune system features innate (non-specific) and adaptive (specific) immunity.
Natural killer cells are non-specific lymphocytes targeting tumor and virus-infected cells.

Inflammatory Response

Inflammation triggers vasodilation and increased vascular permeability, attracting phagocytes to the site of injury or infection.

Antibody Structure and Function

Antibodies consist of two heavy chains and two light chains; their variable region binds to specific antigens.

Blood Pressure Regulation

Short-term regulation involves baroreceptors and chemoreceptors adjusting heart rate and vessel diameter based on pressure and gas levels.
Long-term regulation utilizes renin-angiotensin-aldosterone mechanisms and fluid shift mechanisms to maintain blood volume and pressure.

Cardiovascular Responses

During exercise, blood flow to muscles increases while peripheral resistance decreases; outputs like heart rate and stroke volume rise.
In circulatory shock, baroreceptor reflexes and hormonal responses work to increase blood pressure despite severe drops.

Lymph Nodes and Spleen

Lymph nodes filter lymph and activate immune responses; they are strategically located in areas like the inguinal and axillary regions.
The spleen, containing red and white pulp, functions in immune response and blood filtration.

Interferons and Complement System

Interferons help neighboring cells resist viral infection and activate immune cells.
Complement proteins facilitate destruction of pathogens via cell lysis, phagocytosis, and inflammation, operating through classical or alternative activation pathways.

Effects of Aging and Vascular Health

Atherosclerosis involves material deposition in artery walls.
Arteriosclerosis results in loss of elasticity in major arteries, affecting blood pressure regulation.

Gravity and Blood Pressure

Gravity impacts blood pressure: it raises pressure below the heart and lowers it above while a standing position can complicate venous return due to hydrostatic pressure.### Inflammation and Tissue Repair
Local inflammation leads to classic symptoms: redness, heat, swelling, pain, and loss of function.
Systemic inflammation symptoms include increased neutrophil counts, fever, and shock.

Adaptive Immunity

The adaptive immune system recognizes specific foreign substances and has memory.
It amplifies the inflammatory response and activates the complement system.
Consists of two overlapping arms:
- Antibody-mediated immunity (via antibodies in blood and lymph).
- Cell-mediated immunity (involves lymphocytes).

Antigens and Immune Cells

Antigens are large molecules that trigger an adaptive immune response, categorized into foreign (not produced by the body) and self-antigens (produced by the body).
B cells are responsible for antibody-mediated immunity, working alongside antibodies.
T cells are focused on cell-mediated immunity, targeting infected or abnormal cells.

MHC Class I vs. MHC Class II Molecules

MHC Class I molecules present antigens on nucleated cells, leading to their destruction.
MHC Class II molecules present antigens on antigen-presenting cells, leading to activation of various immune cells.
Lymphocyte activation occurs when their receptors combine with a specific antigenic determinant (epitope).

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Description

This quiz covers the essential functions and structures of blood vessels, including the pathways of blood flow and the dynamics of blood pressure. It also explores the mechanisms of fluid exchange at capillaries. Test your knowledge on how these components work together in the circulatory system.