LECTURE 7

Question 1

Location of the heart

Answer 1

In the mediastinum with the lungs​

Level of the 2nd rib​

Roughly central, but with the base pointing towards the right and the apex towards the left.

Question 2

What is the pericardium

Answer 2

The heart sits in a “bag”: pericardium​

Lubrication (serous)​

Mechanical protections ​

Ie protects it and allows it to move smoothly​

Question 3

3 main layers of pericardium

Answer 3

Pericardium has 3 main layers:​

Fibrous pericardium​

Serous pericardium​

Epicardium

Question 4

What is pericarditis

Answer 4

Problems with the pericardium, which impact the movement and function of the heart.

Question 5

3 main muscle layers of the heart wall

Answer 5

Epicardium​

Myocardium​

Endocardium​

Question 6

Purpose of atrioventricular valves

Answer 6

prevent back flow from Atria to Ventricles

Question 7

Purpose of semilunar valves

Answer 7

prevent backflow from Aorta/Pulmonary artery into the Ventricles​

Question 8

Purpose of chordae tendinae

Answer 8

stop valves acting like a swing door in both directions​

Question 9

Heart valve problems - incompetent valves

Answer 9

Valves (leaflets) do not fully close so there is regurgitant flow i.e. the same blood is pumped around repeatedly (leaky)

Question 10

Heart valve problems - valvular stenosis

Answer 10

stiffened valves caused by repeated infection, congenital disease or calcium deposits. Opening is narrowed so insufficient blood gets through.

Question 11

3 layers of arteries and veins

Answer 11

Tunica adventitia/externa:
supportive outer. Nerves and blood vessels

Tunica media: ​
muscular middle, affects resistance to blood flow (ie involved in control of blood pressure)

Tunica intima: ​
endothelial, inner, layer creates a smooth surface and involved in communication

Question 12

Why is the tunica media the most important layer

Answer 12

Helps move blood along the arteries​

Vasoconstriction of smooth muscle decreases lumen size​

Vasodilation of smooth muscle increases lumen size

Question 13

Large arteries

Answer 13

More muscular walls push blood along to organs.
Distribution role.
Renal, carotid, mesenteric.
Don’t affect BP.
Elastic to absorb high volume and pressure from heart

Question 14

Small arteries

Answer 14

Distribution and resistance.
Highly innervated.
Regulate arterial Pressures.
Receptors for circulating hormones and locally produced signals ie K+ and NO

Question 15

Arterioles

Answer 15

smaller; when constricted, blood flow to organs can be bypassed.
Resistance vessels.
Same as small arteries

Question 16

Capillaries

Answer 16

small and thin to allow for exchange of materials.
No smooth muscle.

Question 17

Types of capillaries

Answer 17

Continuous capillaries
Fenestrated capillaries
Sinusoid capillaries

Question 18

Continuous capillaries

Answer 18

Most common​

Continuous. Gaps only between endothelial cells (tight junctions)​

CNS, lungs, muscle tissue, skin

Question 19

Fenestrated capillaries

Answer 19

Pores of 70-100nm in the capillary wall​

Choroid plexus, kidneys, endocrine glands, villi and ciliary processes of the eye

Question 20

Sinusoid capillaries

Answer 20

Wider gaps in the vessel walls (Lets blood cells through)​

Bone marrow, endocrine glands, placenta

Question 21

2 vessels in venous system

Answer 21

veins and venules

Question 22

Veins

Answer 22

Under less pressure ​

Less smooth muscle (less resistance)​

Stretchy (high capacitance vessels)​

Larger veins have valves to prevent blood flowing backwards.

Question 23

Venules

Answer 23

8-100µm in diameter, more porous than arterioles.​

Capillaries drain into venules​

Continued loss of BP, almost 0 by the time it gets to the vena cava

Question 24

Where can the blood go when it exists the heart

Answer 24

Pulmonary Circulation (RHS)​

Systemic Circulation (LHS)​

Coronary Circulation (from aorta)

Question 25

Pulmonary circulation

Answer 25

Positioned towards back of the heart.​

Crescent shaped​

Blood in through Venae cavae​

Back out through pulmonary artery

Question 26

Systemic circulation

Answer 26

At front and apex​

More circular (thicker walls)​

In through pulmonary veins​

Out through Aorta to aortic arch

Question 27

CORONARY CIRCULATION​

Answer 27

L and R Coronary arteries from the base of the aorta. Shut during contraction​

Coronary arteries branch to supply the heart​

Arteries supply the capillaries for gas and nutrient transfer before draining into the veins

Question 28

What is ABO blood type determined by

Answer 28

different alleles

Question 29

What happens when a blood transfusion occurs with the wrong blood type

Answer 29

the antibodies bind to the RBCs expressing the different antigen. This causes clumping of the RBCs and antibodies (agglutination) and causes severe problems. ​

Question 30

Universal donors

Answer 30

type O blood
do not have A or B antigens​

Make antibodies to A and B​

cannot receive blood from any other blood type.

Question 31

Universal receivers

Answer 31

type AB blood
have A and B antigens​

do not make any A or B antibodies​

Won’t agglutinate donor blood​

their blood can only be given to AB recipients​

Others have antibodies to A, B or both

Question 32

Which blood type alleles are dominant/recessive

Answer 32

Both A and B alleles are dominant over O

Question 33

ABO INCOMPATIBILITY IN BABIES​

Answer 33

Can occur during pregnancy if mother and baby’s blood types are incompatible​

e.g. mother has blood type O and baby is either A or B, and their blood comes into contact or antibodies passed to fetus​

RBCs are broken down causing jaundice, anaemia, and death if severe​

Mother’s antibodies linger after birth and destroy RBC of baby, causing an increase in bilirubin, a neurotoxic yellow waste product ​

Babies with high levels of bilirubin may need phototherapy (oxidises bilirubin and facilitates its removal by the liver) or a blood transfusion​

More severe outcome: (haemolytic disease of newborn) more common in subsequent pregnancies​