Week 21

Question 1

What are the formed elements of blood?

Answer 1

Platelets, WBCs, RBCs

WBCs = White Blood Cells, RBCs = Red Blood Cells

Question 2

What is the composition of blood?

Answer 2

Plasma and formed elements

Question 3

What is the main function of blood plasma?

Answer 3

Solvent for carrying other substances and maintaining osmotic balance

Other functions include absorbing heat and pH buffering.

Question 4

What are the physical characteristics of blood?

Answer 4

Thicker than water, temperature of 100.4°F, pH 7.4, 8% of total body weight, blood volume 5-6 L in males and 4-5 L in females

Question 5

What is venipuncture?

Answer 5

Blood sample taken from a vein with hypodermic needle and syringe

Question 6

What condition is characterized by not enough RBCs or hemoglobin?

Answer 6

Anaemia

Question 7

What is polycythaemia?

Answer 7

Condition with too many RBCs (greater than 65%)

Question 8

What percentage of blood is occupied by cells?

Answer 8

45%

Question 9

What is the lifespan of RBCs?

Answer 9

Approximately 120 days

Question 10

What is the primary function of erythrocytes (RBCs)?

Answer 10

Carry oxygen via hemoglobin

Question 11

What are thrombocytes?

Answer 11

Disc-shaped cell fragments with no nucleus involved in blood clotting

Question 12

What is platelet aggregation?

Answer 12

Activated platelets stick together to form a mass called a platelet plug

Question 13

What is leukocytosis?

Answer 13

A high white blood cell count

Question 14

What is leukopenia?

Answer 14

A low white blood cell count

Question 15

Where does haematopoiesis occur in adults?

Answer 15

In the red bone marrow of flat bones and at the ends of long bones

Question 16

What is acute leukaemia?

Answer 16

Uncontrolled production of immature leukocytes

Question 17

What is bone marrow aspiration?

Answer 17

Procedure to collect bone marrow from the iliac crest

Question 18

What is a bone marrow transplant?

Answer 18

Intravenous transfer of healthy bone marrow

Question 19

What does the heart pump daily?

Answer 19

Approximately 7,000 litres of blood

Question 20

What is the average size of an adult heart?

Answer 20

About 14 cm long and 9 cm wide

Question 21

What is the pericardium?

Answer 21

Membranous sac that encloses the heart

Question 22

What are the two layers of the serous pericardium?

Answer 22

Parietal pericardium and visceral pericardium (epicardium)

Question 23

What is the apex of the heart directed towards?

Answer 23

Anteriorly, inferiorly, and to the left

Question 24

What is the base of the heart directed towards?

Answer 24

Posteriorly, superiorly, and to the right

Question 25

What is the pericardium?

Answer 25

A membranous sac that encloses the heart ## Footnote The pericardium has an outer fibrous layer and an inner serous layer.

Question 26

What are the two layers of the serous pericardium?

Answer 26

* Parietal pericardium * Visceral pericardium (epicardium) ## Footnote The pericardial cavity between these layers contains serous fluid.

Question 27

What are the three distinct layers of the heart wall?

Answer 27

* Epicardium * Myocardium * Endocardium ## Footnote The epicardium protects the heart, the myocardium pumps blood, and the endocardium contains connective tissue.

Question 28

What is the function of the myocardium?

Answer 28

Consists mainly of cardiac muscle tissue that pumps blood out of the heart chambers ## Footnote Cardiac muscle fibers swirl diagonally around the heart.

Question 29

How does the thickness of the myocardium vary?

Answer 29

Thickness varies according to the function of the chamber ## Footnote Atria are thin-walled, while ventricles have much thicker walls.

Question 30

What is the role of the atrioventricular (A-V) valves?

Answer 30

Open to allow blood flow from atria into ventricles and close to prevent backflow ## Footnote A-V valves operate based on pressure differences.

Question 31

When do semilunar valves open?

Answer 31

During ventricular contraction ## Footnote They allow blood to flow into the pulmonary trunk and aorta.

Question 32

What are the two circuits of blood flow?

Answer 32

* Systemic circuit * Pulmonary circuit ## Footnote The systemic circuit involves the left side of the heart, while the pulmonary circuit involves the right side.

Question 33

What is coronary circulation?

Answer 33

The heart's own blood supply ## Footnote It provides oxygen to the active muscle of the heart.

Question 34

What connects cardiac muscle cells?

Answer 34

Intercalated discs ## Footnote These allow action potentials to spread throughout a network of cells.

Question 35

What are autorhythmic cells?

Answer 35

Self-excitable cells that generate spontaneous action potentials ## Footnote They act as a pacemaker for the heart.

Question 36

What does a cardiac cycle consist of?

Answer 36

* Systole (contraction) * Diastole (relaxation) ## Footnote This occurs for both atria and ventricles.

Question 37

How is heart rate regulated?

Answer 37

By the cardiovascular center in the medulla oblongata ## Footnote Factors like proprioceptors, baroreceptors, and chemoreceptors influence heart rate.

Question 38

What effect do epinephrine and norepinephrine have on heart rate?

Answer 38

They increase the rate and force of myocardial contractions ## Footnote Thyroid hormones also affect heart rate.

Question 39

True or False: The myocardium of the left ventricle is thinner than that of the right ventricle.

Answer 39

False ## Footnote The left ventricle has a much thicker myocardium.

Question 40

Fill in the blank: Atria are _______ walled, delivering blood to adjacent ventricles.

Answer 40

thin

Question 41

What is the function of the fibrous skeleton of the heart?

Answer 41

Provides support for heart valves and serves as an electrical insulator ## Footnote It merges with the interventricular septum.

Question 42

What happens when A-V valves close?

Answer 42

They prevent backflow of blood into atria ## Footnote This occurs when ventricles contract.

Question 43

What is functional syncytium?

Answer 43

A unit formed by cardiac cells contracting together ## Footnote This allows for coordinated heart contractions.

Question 44

What happens to heart rate during hyperkalaemia?

Answer 44

It decreases the rate and force of myocardial contractions ## Footnote An excess of potassium ions in the blood leads to this condition.

Question 45

What physical factors can influence heart rate?

Answer 45

* Age * Gender * Physical fitness * Temperature ## Footnote A rise in body temperature typically increases heart rate.