circulatory/cardiovascular system 2

Question 1

Myogenic

Answer 1

The heart is myogenic which means it can generate its own contractions.

Question 2

Sinoatrial (SA) node

Answer 2

The sinoatrial (SA) node in the right atrium initiates each heartbeat. The SA node sends electrical signals at regular intervals which causes the heart to beat.

Question 3

Process of propagation of the signal in heart contraction

Answer 3

The SA node sends out electrical signals to reach the AV node. From the AV node, the signal is relayed via the bundle of His and spreads to the ventricles via the Purkinje fibers.

Question 4

Cardiac accelerator nerve versus vagus nerve

Answer 4

The cardiac accelerator nerve stimulates the heart to beat faster. The vagus nerve stimulates the heart to beat slower.

Question 5

How and why does exercise increase heart rate?

Answer 5

Increased activity means more respiration, causing a greater need for oxygen and increased production of CO2. Increased CO2 in the blood will decrease its pH. When this happens, impulses are sent along the cardiac accelerator nerve to the SA node which increases heart rate.

Question 6

Epinephrine (adrenalin)

Answer 6

Epinephrine (adrenalin) increases heart rate to prepare for vigorous physical activity in 2 ways. The first way is by stimulating the SA node to emit electrical signals at a faster rate. The second way is by increasing the amount of impulses generated by the SA and AV nodes.

Question 7

Atheromas

Answer 7

Atheromas are fatty deposits caused by high blood concentrations of cholesterol and fats in the arteries. These deposits build up over time and eventually block arteries which leads to cardiovascular issues.

Question 8

Thrombosis

Answer 8

Thrombosis is the clotting within a blood vessel that blocks the blood vessel entirely. If a coronary artery is blocked, the cells in that part of the heart die and a heart attack occurs.

Question 9

Pharynx versus larynx

Answer 9

The pharynx is a membrane-lined cavity found behind the nose and mouth that connects to the esophagus and trachea. The larynx is a muscular tube that connects our mouth to our lungs.

Question 10

Trachea

Answer 10

The trachea is a tube that connects to the larynx and bronchial tubes. It is reinforced by cartilage which allows it to flex during breathing.

Question 11

Bronchi versus bronchioles

Answer 11

The bronchi are airways that conduct air into the lungs. The bronchioles are branches from the bronchi; they are lined by smooth muscle that can dilate and constrict.

Question 12

Alveoli

Answer 12

The alveoli are tiny air sacs of lungs that convert oxygen into carbon dioxide.

Question 13

Diaphragm

Answer 13

The diaphragm is a muscle that contracts rhythmically and continuously which allows us to breathe.

Question 14

Ventilation, gas exchange, and respiration

Answer 14

Ventilation removes lower oxygenated air within the alveoli and replaces it with higher oxygenated air. Gas exchange ensures oxygen is always diffusing into the blood from the alveoli, while at the same time ensuring that CO2 diffuses out of the blood into the alveoli. Respiration facilitates inhalation and exhalation of the lungs.

Question 15

Type 1 and type 2 pneumocytes

Answer 15

Type 1 pneumocytes are thin, flattened cells that increase the amount of surface area available for diffusion to occur. Type 2 pneumocytes are rounded cells that create a moist surface inside the alveoli to prevent the sides from sticking to each other. Both pneumocyte types speed up the process of gas exchange.

Question 16

Inspiration (inhalation) versus expiration (exhalation)

Answer 16

During inspiration/inhalation, the external muscles contract. Then, diaphragm contracts and abdominal muscles relax. This process decreases pressure in the lungs as the volume increases, allowing air to enter. Vice versa occurs during exhalation. During expiration/exhalation, the internal muscles contract. Then, the diaphragm relaxes and the abdominal muscles contract. This process increases pressure in the lungs as the volume decreases, allowing air to escape.

Question 17

Emphysema

Answer 17

Emphysema is caused by long-term exposure to cigarette smoke and other pollutants. It causes the lungs to swell which makes ventilation and gas exchange more difficult for the body.

Question 18

Single versus double circulation

Answer 18

In single circulation, blood flows to and from the heart through a single pathway. In double circulation, oxygenated and deoxygenated blood flows through two separate pathways which are connected to the heart.

Question 19

Systole versus diastole + cardiac cycle

Answer 19

Cardiac cycle events can be divided into systole and diastole. During systole, blood pressure increases and the cardiac muscles contract. During diastole, blood pressure decreases and the cardiac muscles relax. Additionally, the cardiac cycle begins with atrial systole, then atrial diastole, then ventricular systole, then the semilunar valves close to prevent backflow, then ventricular diastole.

Question 20

Sympathetic versus parasympathetic nervous system

Answer 20

The sympathetic nervous system releases hormones such as epinephrine to accelerate the heart rate. The parasympathetic nervous system releases the hormone acetylcholine to slow the heart rate.