Immunology and Blood Components

Questions and Answers

What are the three types of lymphocytes?

B cells, T cells, NK cells (correct)

M cells, T cells, NK cells

B cells, A cells, NK cells

B cells, T cells, C cells

What is the primary function of platelets?

Fight infections

Promote vascular spasm and blood clotting (correct)

Transport oxygen

Produce hormones

Where does the heart rest in the body?

Above the lungs

On the diaphragm near the midline of the thoracic cavity (correct)

In the abdominal cavity

In the pelvic cavity

What is the average mass of the heart in adult males?

300 g Signup and view all the answers

What component of blood protects against disease?

White blood cells Signup and view all the answers

What is the long axis measurement of the heart?

12 cm Signup and view all the answers

Which part of the heart is described as the pointed tip?

Apex Signup and view all the answers

How many cm deep is the heart from anterior to posterior?

6 cm Signup and view all the answers

What is primarily responsible for blood clotting?

Platelets Signup and view all the answers

What is the primary function of capillaries?

Exchange of substances between blood and interstitial fluid Signup and view all the answers

Which of the following arteries is classified as an elastic artery?

Aorta Signup and view all the answers

What is the role of valves in veins?

Prevent backflow of blood Signup and view all the answers

How do muscular venules differ from postcapillary venules?

Muscular venules are larger and have thicker walls Signup and view all the answers

What is meant by the term 'resistance vessel' in relation to elastic arteries?

They oppose blood flow due to friction Signup and view all the answers

Which of the following best describes the specific size of capillaries?

5-10 μm in diameter Signup and view all the answers

What is the remnant of the ductus arteriosus called after it closes?

Ligamentum arteriosum Signup and view all the answers

Which heart chamber is the thickest?

Left ventricle Signup and view all the answers

Which valve is located between the right atrium and the right ventricle?

Tricuspid valve Signup and view all the answers

What type of valve is the left atrioventricular valve considered to be?

Bicuspid valve Signup and view all the answers

What structure connects the pulmonary trunk and the aortic arch?

Ligamentum arteriosum Signup and view all the answers

Which structure receives blood from the lungs?

Left atrium Signup and view all the answers

What feature is present in the left ventricle for anchoring the valve cusps?

Chordae tendineae Signup and view all the answers

What is the primary function of the atrioventricular valves?

Prevent backflow into the atria Signup and view all the answers

How many pulmonary veins are there that carry blood from the lungs to the heart?

Four Signup and view all the answers

Which part of the heart's left atrium has a smooth internal wall?

Posterior wall Signup and view all the answers

What is the function of the interatrial septum?

To separate the right and left atrium Signup and view all the answers

What is the fossa ovalis a remnant of?

The foramen ovale Signup and view all the answers

Which valve is also known as the tricuspid valve?

Right atrioventricular valve Signup and view all the answers

What separates the right ventricle from the left ventricle?

Interventricular septum Signup and view all the answers

What structure shunts blood from the pulmonary trunk into the aorta during fetal life?

Ductus arteriosus Signup and view all the answers

What type of tissue composes the heart valves?

Dense connective tissue Signup and view all the answers

What structure is located within the right atrium?

Fossa ovalis Signup and view all the answers

Which blood vessel carries blood to the heart wall?

Coronary arteries Signup and view all the answers

What does the aortic arch carry blood to?

Throughout the body Signup and view all the answers

What is the role of papillary muscles in the heart?

Anchoring the chordae tendineae Signup and view all the answers

What is the primary function of the sinoatrial (SA) node?

To initiate and regulate heart muscle contractions Signup and view all the answers

What percentage of cardiac cells are self-excitable?

1% Signup and view all the answers

What best describes depolarization in cardiac cells?

A response to an external stimulus that alters membrane potential Signup and view all the answers

Which structure in the heart is responsible for the drainage of the right ventricle directly into the right atrium?

Anterior cardiac vein Signup and view all the answers

What is meant by the term 'excitable' in the context of cardiac cells?

The ability to respond to stimuli by changing membrane potential Signup and view all the answers

What aspect of cardiac cells allows them to contract in a continuous way?

Their inherent excitability Signup and view all the answers

What kind of system is the intrinsic conduction system of the heart?

A mechanism that allows involuntary heart muscle contractions Signup and view all the answers

Where is the sinoatrial (SA) node located?

In the wall of the right atrium Signup and view all the answers

Which of the following best describes the relationship between the sinoatrial (SA) node and the rest of the cardiac cells?

SA node cells generate impulses without any external help Signup and view all the answers

What role does the anterior cardiac vein play in the heart's anatomy?

It drains blood from the right ventricle Signup and view all the answers

Study Notes

Lymphocytes and Blood Protection

Lymphocytes include B cells, T cells, and natural killer (NK) cells.
Blood can clot, preventing excessive loss after injury.
White blood cells engage in phagocytosis to protect against diseases.
Platelets are cell fragments lacking a nucleus that release chemicals to aid blood clotting and vascular spasm.

Anatomy of the Heart

The heart is approximately the size of a closed fist and rests on the diaphragm near the thoracic cavity's midline.
Heart dimensions:
- Long axis: 12 cm (5 in)
- Width: 9 cm (3.5 in)
- Depth: 6 cm (2.5 in)
- Average mass: 250 g (8 oz) in females; 300 g (10 oz) in males.
The heart is located in the mediastinum, with two-thirds of its mass to the left of the midline.

Heart Structure

Apex: The pointed tip formed by the left ventricle.
Interatrial septum separates the right and left atria.
Fossa ovalis: A depression in the interatrial septum, a remnant from fetal development.
Right atrioventricular (tricuspid) valve: Controls blood flow from right atrium to right ventricle.

Cardiac Valves

Heart valves are made of dense connective tissue covered by endocardium.
Left atrium receives blood from the lungs via four pulmonary veins.
Blood flows from the left atrium to the left ventricle through the left atrioventricular valve (bicuspid/mitral valve).
The left ventricle is the thickest heart chamber with an average thickness of 10-15 mm (0.4-0.6 in).

Specialized Cardiac Tissues

Myocytes are responsible for heart contraction and include trabeculae carneae and chordae tendineae.
Excitability allows cardiac cells to respond to stimuli and initiate action potentials.

Heart Conduction System

The intrinsic conduction system consists of self-excitable cardiac cells (1% of total).
The sinoatrial (SA) node, or pacemaker, is located in the right atrium wall, synchronizing heart contractions.

Blood Vessel Overview

Elastic (conducting) arteries, such as the aorta, are key to regulating blood flow and act as pressure reservoirs.
Postcapillary venules receive blood from capillaries, while muscular venules have thicker walls for substance exchange.
Capillaries connect arterial outflow to venous return and facilitate the exchange of substances.

Veins

Veins have thin walls and diameters ranging from 0.5 mm in small veins to 3 cm in major venae cava.
Many veins, especially in limbs, contain valves to prevent backflow, aiding venous return.

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Description

This quiz covers key concepts related to lymphocytes, including B cells, T cells, and natural killer cells. Additionally, it provides insights into the role of blood in clotting and disease protection through white blood cells and platelets. Test your knowledge on these essential topics in immunology and blood physiology.