Cardiovascular System - The Heart

Question 1

Histology- cardiomyocytes(only in the heart

Answer 1

• short thick branches cells that contain one or sometime two nuclei
• intercalated disc have electrical gap junctions to stimulate each other so that they can pass ions freely between cells and allow electrical signals to trigger contraction that goes from cell to cell
• smooth sarcoplasmic reticulum. It’s critical for calcium storage and the necessary for muscle contractions
• lesser t tubules but larger then skeletal muscles and losses connection

Function properties: contract in unison ( have to contract at once to allow for effective blood pumping). Autonomic ( they don’t require any conscious control and are regulated by the autonomic nervous system. Fatigue resistant ( they have lots of mitochondria and continuous blood supply and can function without tiring

Question 2

Metabolism of cardiac muscles

Answer 2

• cardiac muscle depends almost exclusively on aerobic respiration used to make ATP ( requires oxygen)
- rich in myoglobin( type of protein in muscle cells that allow for long sustain in respiration) and glycogen ( serves as a reserve to quickly change glucose to energy when we need it)
- large mitochondria ( more effectively meet the high demands of respiration and energy production in the cells)

• fuel for energy production
- fatty acids 60%
- glucose 35%
- ketones
- lactic acid
- Amino acids
Need to keep high oxygen to heart

Question 3

Pulmonary and systemic circulation

Answer 3

•pulmonary circuit
Where blood come from the right ventricle to the pulmonary artery and it Carrie’s the oxygen out of the blood from the heart to the lungs. Pulmonary artery is some what unique as it Carrie’s deoxygenated blood. Then oxygen rich blood returns back to the heart by the circulatory veins.

• systemic circuit
It allows oxygen rich blood to be pumped from the left ventricle to the rest of the body. It travels via the atria to small arteries and artierioles and ultimately to capillaries when nutrients and oxygen are delivered to the tissues. After changing oxygen for carbon dioxide at the cellular level that deoxygenated blood then travels back to the heart

Question 4

The heart wall - pericardium

Answer 4

Double walled sac ( pericardial sac) that encloses the heart

• fibrous pericardium: tough fibrous outer wall
- anchored to diaphragm sternum mediastinal tissue

• serous pericardium: deep thin membrane
- parietal layer: lines fibrous pericardium
- visceral layer: adheres to heart surface, forms outermost layer of the heart (ie epicardium)
- pericardial cavity- space inside the pericardial sac filled with pericardial fluid
- allows heart to beat without friction provides room to expand yet resists excessive expansion

Question 5

Heart wall

Answer 5

Epicardium
- it’s primarily comprised of connective tissue and fat and contains the epicardium arteries and veins
- main function is to be there as a lubricant and protective layer. Also the site where cononary blood vessels travel through the heart

Myocardium
- middle layer of the heart and is made up of cardiac muscles
- the thickness is proportional to the workload of each chamber
- main function is the pumping action of the heart itself. Muscle spirals around the heart which produces wringing motion

Endocardium
- smooth inner lining of the heart and blood vessels
- covers the valve surfaces and is continuous with endothelium of blood vessels
- main function is to provide a smooth surface for blood to flow over and reduce the likelihood of blood clot formation

• fibrous skeleton of the heart: framework of collagenous and elastic fibres found within the heart and provide structural support

Question 6

Chamber of the heart 4 chambers

Question 7

Sulci of the heart

Answer 7

Grooves that seperate chambers of the heart

Sulci contains coronary arteries ( where the heart itself has its own system of blood vessels so that it can be oxygenated itself

Coronary sulcus
- separates atria and ventricles

Anterior interventricular sulcus

Posterior interventricular sulcus

Question 8

The valves

Answer 8

Av valves
- control blood flow between atria and ventricles

Semilunar valves
- control the flow of blood into the bodies main to arteries
- prevent back flow of blood

Valves open and close under pressure not muscles

Question 9

Coronary circulation

Question 10

The ventricles of the heart are responsible for

Answer 10

Pumping blood to the lungs and body
Receive blood from atria

Question 11

The hearts natural pacemaker is the

Answer 11

Sinoatrial node

Question 12

The inner most layer of the heart wall

Answer 12

Endocardium

Question 13

Which chamber of the heart pump’s deoxygenated blood to the lungs

Answer 13

Right ventricle

Question 14

What are the blood vessels that supply blood to the heart muscles itself

Answer 14

Coronary arteries

Question 15

The heart muscle is also referred to as

Answer 15

Myocardium

Question 16

Which of the following is the thin double layer membrane that surrounds the heart

Answer 16

Pericardium