heart quizzy poo

Question 1

pathway of blood (1)

Answer 1

Oxygenated blood is carried from the left ventricle, through the arteries, and to the capillaries. Capillaries are the smallest/thinnest blood vessels and they connect arteries and veins.

Question 2

pathway of blood (2)

Answer 2

From the capillaries, the deoxygenated blood returns to the heart through a system of veins and enters the right atrium. Veins carry blood toward the heart. Pulmonary circulation moves blood between the heart and the lungs. It transports deoxygenated blood to the lungs to absorb oxygen and release carbon dioxide. The oxygenated blood then flows back to the heart.

Question 3

systemic circulation

Answer 3

Systemic circulation moves blood between the heart and the rest of the body.

Question 4

double circulation

Answer 4

Double circulation supports a strict separation of both oxygenated and deoxygenated blood. Therefore, this circulation ensures that the body always has a dedicated supply of oxygen and also, it improves body efficiency.

Question 5

pulmonary circulation

Answer 5

The pulmonary arteries function to transport deoxygenated blood from the right side of the heart to the lungs for oxygenation. These vessels serve as the conduit between the right side of the heart and the lungs

Question 6

roles of valves in the heart

Answer 6

The valves prevent the backward flow of blood. These valves are actual flaps that are located on each end of the two ventricles (lower chambers of the heart). They act as one-way inlets of blood on one side of a ventricle and one-way outlets of blood on the other side of a ventricle.

Question 7

events in the cardiac cycle

Answer 7

The cardiac cycle is the performance of the human heart from the beginning of one heartbeat to the beginning of the next. It consists of two periods: one during which the heart muscle relaxes and refills with blood, called diastole, following a period of robust contraction and pumping of blood, called systole. The SA (sinoatrial) node generates an electrical signal that causes the upper heart chambers (atria) to contract. The signal then passes through the AV (atrioventricular) node to the lower heart chambers (ventricles), causing them to contract, or pump. The SA node is considered the pacemaker of the heart.

Question 8

control of heartbeat - myogenic/SA node

Answer 8

Within the wall of the right atrium is a specialized cluster of cardiomyocytes that direct the contraction of heart muscle tissue. This cluster of cells is collectively called the sinoatrial node (SA node or SAN). The sinoatrial node acts as the primary pacemaker – controlling the rate at which the heart beats (i.e. pace ‘making’).

Question 9

control of heart bt medulla

Answer 9

Two nerves connected to the medulla regulate heart rate by either speeding it up or slowing it down: The sympathetic nerve releases the neurotransmitter noradrenaline (a.k.a. norepinephrine) to increase heart rate. The parasympathetic nerve (vagus nerve) releases the neurotransmitter acetylcholine to decrease heart rate. Hormones are chemical messengers released into the bloodstream that act specifically on distant target sites (like the heart)

Question 10

control of heartbeat adrenal glands

Answer 10

Heart rate can undergo a sustained increase in response to hormonal signaling in order to prepare for vigorous physical activity. The hormone adrenaline (a.k.a. epinephrine) is released from the adrenal glands (located above the kidneys). Adrenaline increases heart rate by activating the same chemical pathways as the neurotransmitter noradrenaline

Question 11

structure of cardiac muscle

Answer 11

Cardiac muscle fibers cells also are extensively branched and are connected to one another at their ends by intercalated discs. An intercalated disc allows the cardiac muscle cells to contract in a wave-like pattern so that the heart can work as a pump.

Question 12

defibrillator and artificial pacemaker

Answer 12

Pacemaker and defibrillator allow for cardiac cells in the heart to act in unison. Without them, cardiac cells with act independently.

Question 13

blood vessel structure

Answer 13

Arteries have thick walls and narrow lumens because they transport blood at high pressure
Capillaries have walls that are only a single cell thick because they exchange materials between blood and tissue
Veins have thin walls with wide lumens and valves because they transport blood at low pressure

Question 14

components of the blood

Answer 14

plasma, erythrocytes, leukocytes, platelets

Question 15

plasma

Answer 15

Plasma (liquid/ fluid
component of the blood –
water based) ~55%

Question 16

erythrocytes

Answer 16

(red blood cells
– transport O2) ~45%

Question 17

leukocytes

Answer 17

(white blood cells)
Phagocytes (nonspecific
immunity)
Lymphocytes (specific immunity)

Question 18

platelets

Answer 18

(involved in blood clotting)
Note: Leukocytes and platelets make up less than 1% of the blood

Question 19

how materials are exchanged between the capillaries and tissues

Answer 19

They have a very small diameter (~ 5 µm wide) which allows passage of only a single red blood cell at a time (optimal exchange)
The capillary wall is made of a single layer of cells to minimize the diffusion distance for permeable materials
They are surrounded by a basement membrane which is permeable to necessary materials
They may contain pores to further aid in the transport of materials between tissue fluid and blood
Material that exits the capillaries at body tissues includes oxygen and nutrients (needed by the cells for respiration)
Materials that enter the capillaries of body tissues include carbon dioxide and urea (wastes produced by the cells)

Question 20

role of valves in veins

Answer 20

Because the pressure is low, veins possess valves to prevent backflow and stop the blood from pooling at the lowest extremities

Question 21

atherosclerosis

Answer 21

Atherosclerosis is the hardening and narrowing of the arteries due to the deposition of cholesterol

Atheromas (fatty deposits) develop in the arteries and significantly reduce the diameter of the lumen (stenosis)
The restricted blood flow increases pressure in the artery, leading to damage to the arterial wall (from shear stress)
The damaged region is repaired with fibrous tissue which significantly reduces the elasticity of the vessel wall
As the smooth lining of the artery is progressively degraded, lesions form called atherosclerotic plaques
If the plaque ruptures, blood clotting is triggered, forming a thrombus that restricts blood flow
If the thrombus is dislodged it becomes an embolus and can cause a blockage in a smaller arteriole

Question 22

consequences of occlusions

Answer 22

Atherosclerosis can lead to blood clots which cause coronary heart disease when they occur in coronary arteries

Myocardial tissue requires the oxygen and nutrients transported via the coronary arteries in order to function
If a coronary artery becomes completely blocked, an acute myocardial infarction (heart attack) will result
Blockages of coronary arteries are typically treated by by-pass surgery or creating a stent (e.g. balloon angioplasty)

Question 23

risk factors of CHD

Answer 23

Age – Blood vessels become less flexible with advancing age
Genetics – Having hypertension predisposes individuals to develop CHD
Obesity – Being overweight places an additional strain on the heart
Diseases – Certain diseases increase the risk of CHD (e.g. diabetes)
Diet – Diets rich in saturated fats, salts, and alcohol increases the risk
Exercise – Sedentary lifestyles increase the risk of developing CHD
Sex – Males are at greater risk due to lower estrogen levels
Smoking – Nicotine causes vasoconstriction, raising blood pressure

Question 24

systolic pressure

Answer 24

The systolic pressure is a higher value that represents the pressure in the vessel when the heart is contracting (i.e. pulse flow)

Question 25

diastolic pressure

Answer 25

The diastolic pressure is a lower value that represents the pressure in the vessel when the heart is relaxing

Question 26

high blood pressure

Answer 26

High blood pressure usually develops over time. It can happen because of unhealthy lifestyle choices, such as not getting enough regular physical activity. Certain health conditions, such as diabetes and having obesity, can also increase the risk for developing high blood pressure.

Question 27

measuring blood pressure

Answer 27

Measuring blood pressure:
Increase cuff pressure to block artery/
arterial blood flow
As release pressure, first sound is
systolic pressure (pressure in artery>
pressure in cuff; forces blood through)
When NO MORE sound = diastolic pressure (diastolic pressure > cuff pressure)

Question 28

hypertension

Answer 28

Causes of Hypertension: fat deposition in arteries (narrower lumen), plaque deposits in arteries (narrower lumen/ loss of elasticity), high salt diet (more fluid retention in blood/ blood to pump), smoking (nicotine = vasoconstriction), certain medications, stress/ stress hormones (vasoconstriction), genetics
consequences: stroke, thrombosis/ blood clots, heart attack, heart failure, coronary heart disease (CHD)