Circulatory System Quiz

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Questions and Answers

What is the main function of precapillary sphincters in capillary beds?

To facilitate gas exchange between blood and tissues

To increase blood pressure in capillaries

To control blood flow into the capillary bed (correct)

To transport nutrients away from the capillaries

Which type of capillary is characterized by having a complete lining?

Fenestrated capillaries

Sinusoidal capillaries

Continuous capillaries (correct)

Transitional capillaries

Which of the following is true regarding venules?

They are the largest type of veins

They contain no valves

They carry oxygenated blood exclusively

They are companion vessels with arterioles (correct)

What is a major role of valves found in most veins?

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

What defines sinusoids among the types of capillaries?

They allow large molecules and cells to pass through gaps Signup and view all the answers

What is the primary function of the tunica intima in blood vessels?

Lining the lumen of the blood vessel Signup and view all the answers

Which type of artery is characterized by a large diameter and the presence of elastic fibers?

Elastic arteries Signup and view all the answers

What structure supplies blood to the larger blood vessels?

Vasa vasorum Signup and view all the answers

Which component primarily distinguishes muscular arteries from elastic arteries?

Thicker tunica media Signup and view all the answers

What is the primary role of capillaries in the circulatory system?

Facilitating metabolic exchange between blood and tissues Signup and view all the answers

What is the primary function of the cardiovascular system?

Transport blood throughout the body Signup and view all the answers

Which side of the heart receives oxygen-poor blood?

Right atrium Signup and view all the answers

What separates the right and left ventricles?

Interventricular septum Signup and view all the answers

What is the role of the atrioventricular valves?

Prevent backflow into the atria Signup and view all the answers

How many cusps does each semilunar valve have?

Three Signup and view all the answers

Which structure normally prevents backflow from major arteries into the ventricles?

Semilunar valves Signup and view all the answers

What anatomical feature is NOT found between the major veins and the atria?

Aortic valve Signup and view all the answers

What occurs during a heart valve disorder characterized by an incompetent valve?

Blood leaks back into the atria Signup and view all the answers

What is the pericardium's main function?

Protect and enclose the heart Signup and view all the answers

Where is the heart located in the thoracic cavity?

Left of midline Signup and view all the answers

What do arteries and veins in the body typically have in common?

They often run side by side. Signup and view all the answers

Which artery branches off the ascending aorta?

Brachiocephalic trunk Signup and view all the answers

Which of the following arteries supplies the lower limbs?

Common iliac artery Signup and view all the answers

What is the primary purpose of the internal and external jugular veins?

To drain blood from the head. Signup and view all the answers

Where does blood from the lower limbs eventually drain into?

Great saphenous and femoral veins Signup and view all the answers

Which artery continues from the abdominal aorta to supply the lower limbs?

Femoral artery Signup and view all the answers

Which veins merge to form the superior vena cava?

Brachiocephalic veins Signup and view all the answers

Which artery branches into the anterior and posterior tibial arteries?

Popliteal artery Signup and view all the answers

What happens to the valves in the case of valvular stenosis?

Valves become hardened Signup and view all the answers

Which structure receives deoxygenated blood from the body?

Right atrium Signup and view all the answers

What is the main reason for the thick muscular walls of the left ventricle?

To generate higher pressure for systemic circulation Signup and view all the answers

What is known as the functional blood supply to the heart muscle itself?

Coronary circulation Signup and view all the answers

What is the primary risk of a myocardial infarction?

Blockage in one of the coronary arteries Signup and view all the answers

Which of the following pairs correctly match the heart valve to its location?

Pulmonary semilunar valve - right ventricle Signup and view all the answers

Why is the pulmonary circuit considered a low-pressure system?

It is a short circuit to the lungs Signup and view all the answers

What are the primary components of the serous pericardium?

Visceral layer and parietal layer Signup and view all the answers

What is the primary function of lymph nodes?

Cleansing lymph by removing debris and activating lymphocytes Signup and view all the answers

Which lymphatic duct drains the right upper limb and right side of the head?

Right lymphatic duct Signup and view all the answers

What is the primary role of the thymus?

Maturation of T-cells Signup and view all the answers

Which of the following describes specialized lymphatic capillaries found in the intestine?

Lacteals Signup and view all the answers

What are the two main types of lymphoid organs?

Primary and secondary lymphoid organs Signup and view all the answers

What major function does the spleen serve?

Lymphocyte storage and proliferation Signup and view all the answers

What is the primary role of the reticular connective tissue in lymphoid organs?

Housing and development of lymphocytes Signup and view all the answers

How does lymph enter the lymph nodes?

Through afferent lymphatic vessels Signup and view all the answers

What does MALT stand for, and what is its purpose?

Mucosa-associated lymphoid tissue; protects against mucosal pathogens Signup and view all the answers

Which structure serves to clean lymph and activate lymphocytes?

Lymph nodes Signup and view all the answers

Study Notes

Cardiovascular System

Transports blood throughout the body
Blood carries oxygen, nutrients, wastes, and hormones
A system of blood vessels and a heart
Network of blood vessels approximately 100,000 km long

Heart Anatomy

Approximately the size of a fist
Right side: receives oxygen-poor blood from tissues, pumps blood to the lungs for CO2 removal and O2 uptake via pulmonary circuit
Left side: receives oxygenated blood from the lungs, pumps blood to body tissues via systemic circuit

Heart Anatomy (Chambers)

Receiving chambers: right atrium (receives blood from systemic circuit), left atrium (receives blood from pulmonary circuit)
Pump chambers: right ventricle (pumps blood through pulmonary circuit), left ventricle (pumps blood through systemic circuit)
Interventricular septum: separates right and left ventricles

Heart Position in Thoracic Cavity

Left of midline
Deep to sternum
Located in the mediastinum
Base: left atrium, superior border, great vessels, and superior vena cava
Apex: tip of left ventricle, inferior border

Pericardium

Encloses the heart
Restricts movement (allows slight movement)
Composed of two parts:
- Fibrous pericardium
- Serous pericardium (parietal and visceral layers); pericardial cavity between these layers

External Heart Anatomy and Features

Atria: receiving chambers, auricles (muscular extensions)
Coronary Sulcus: groove separating atria and ventricles
Anterior Interventricular Sulcus: groove separating ventricles

Posterior Interventricular Sulcus

Located between the right and left ventricles

Heart Valves

Ensure unidirectional blood flow through the heart
Open and close in response to pressure changes
No valves are found between major veins and atria (inertia of incoming blood prevents backflow)
Heart contractions compress venous openings

Atrioventricular (AV) Valves

Prevent backflow into atria
Chordae tendineae (attachment)
Papillary muscles
- Tricuspid valve (right AV valve): between right atrium and ventricle
- Mitral valve (left AV valve, bicuspid valve): lies between left atrium and ventricle

Semilunar (SL) Valves

Two semilunar valves prevent backflow from major arteries back into ventricles
- Pulmonary semilunar valve
- Aortic semilunar valve

Heart Valve Disorders

Incompetent valve: valve does not close tightly
Valvular stenosis: valves become hardened
Defective valves can be replaced (mechanical, animal or cadaver valves)

Pathway of Blood Through Heart (Right Side)

Superior vena cava (SVC), inferior vena cava (IVC), and coronary sinus
Right atrium
Tricuspid valve
Right ventricle
Pulmonary semilunar valve
Pulmonary trunk
Pulmonary arteries
Lungs

Pathway of Blood Through Heart (Left Side)

Four pulmonary veins
Left atrium
Mitral valve
Left ventricle
Aortic semilunar valve
Aorta
Systemic circulation

Coronary Circulation

Functional blood supply to heart muscle itself
Delivered when heart is relaxed
Right and left coronary arteries (within coronary sulcus)
Myocardial infarction: results from a blockage in one of these vessels.

Anatomy of Blood Vessels

Three classes
- Arteries
- Capillaries
- Veins
Arteries and veins entering and leaving the heart are 'great vessels'

Blood Vessel Tunics

Tunica intima
Tunica media
Tunica externa

Arteries

Three types
- Elastic arteries
- Muscular arteries
- Arterioles

Elastic Arteries

Largest
Near heart
Branches into muscular arteries

Muscular Arteries

Medium-sized
Elastic fibers in two concentric rings between the three tunics (internal and external elastic lamina)
Have thicker tunica media

Arterioles

Smallest
Less than six cell layers of smooth muscle in tunica media
Sympathetic and parasympathetic innervation

Capillaries

Smallest blood vessels
Small diameter, Erythrocyte travel
Wall is only tunica intima (single layer)
Metabolic exchange occurs

Capillary Beds

Some capillary beds are fed by a metarteriole
A thoroughfare channel connects to a venule
Branches from metarteriole = capillaries (ring of smooth muscle on their walls are true capillaries)

Types of Capillary Beds

Continuous
Fenestrated
Sinusoids

Veins and Venules

Return blood to heart
Pressure lower than arteries
Blood reservoirs

Venules

Smallest veins
Companion vessels with arterioles
Smallest are postcapillary venules (Leukocytes may pass through)
Venules form veins

Veins

Larger than venules
Smaller/medium-sized travel with muscular arteries
Large veins travel with elastic arteries
Most veins contain valves to prevent pooling
Formed from tunica intima
Venous return

Lymphatic System

Returns fluid that leaks out of blood vessels
Lymph: Fluid approximately 3L circulated per day
Lymphatics: Network of vessels
Contains immune cells: Lymph nodes, spleen, thymus, tonsils, other tissues

Lymphatic Capillaries

Highly-permeable, blind-ended vessels
Weave between blood capillaries and tissue cells
Absent in bone and tooth tissues
Loosely overlapping endothelial cells form minivalves
Specialized lymphatic capillaries in the intestine are called lacteals (help absorb fat)

Lymphatic Vessels

Structure is similar to veins, but contain more valves
Lymph capillaries drain into larger collecting lymphatic vessels
Lymph drains into larger lymphatic trunks
Finally, drains one of two lymphatic ducts

Lymphatic Organs

Lymphoid organ tissue mainly comprised of reticular connective tissue
Houses and allows lymphocyte development
Two main types
- Primary Lymphoid Organs (red bone marrow and thymus) - sites for T and B cell maturation
- Secondary Lymphoid Organs (lymph nodes, spleen, tonsils, MALT, appendix) sites of lymphocyte activation

Lymphatic Organs: Lymph Nodes

Hundreds throughout body (deep and near surface)
Common body surface regions: cervical, axillary, and inguinal
Functions: cleansing lymph by removing debris and organisms (using macrophages); area for lymphocyte activation

Lymphatic Organs: Lymph Node Structure

Surrounded by a fibrous capsule
Capsule extends inward into trabeculae, to divide the node.
Two regions: outer cortex and inner medulla
Lymph enters through afferent lymphatic vessels, travels through several sinuses
Lymph exits from efferent lymphatic vessels

Lymphatic Organs: Thymus

Bi-lobed organ inferior to neck
T-cells mature (more in 230), most active in childhood
Immature T-cells kept from blood via blood-thymus barrier
Primarily epithelial cells instead of reticular connective tissue

Lymphatic Organs: MALT

Mucosa-associated lymphoid tissue
Protects body from pathogens entering through mucosal barriers
Includes: tonsils, Peyer's patches, appendix

Review Questions (Cardiovascular System)

Why is the left ventricular wall thicker than the right?
What are the 2 parts of the serous pericardium?
Freshly oxygenated blood is first received by which part of the heart? Where is deoxygenated blood received?
What are the names and locations of the 4 heart valves?

Review Questions (Lymphatic System)

Describe the pathway of lymphatic flow from a tissue to the heart
What is MALT? What role does it play?
Why do lymph nodes under your arms sometimes swell after a vaccination?

Important Structures in Cardiovascular System

Aorta
Pulmonary trunk
Pulmonary arteries
Superior vena cava
Inferior vena cava
Coronary sinus
Right atrium
Right ventricle
Pulmonary semilunar valve
Tricuspid valve
Left atrium
Left ventricle
Aortic semilunar valve
Mitral valve

Important Structures in Lymphatic System

Right Lymphatic Duct
Thoracic Duct
Lymph nodes (cervical, axillary, and inguinal)
Spleen
Thymus
Tonsils

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Description

Test your knowledge on the circulatory system with this quiz! Questions cover various aspects, including blood vessels, heart function, and types of capillaries. Challenge yourself to understand how these components work together to maintain circulation in the body.