Cardiac Flashcards
Describe the location of the heart in the body
Midline and ventrally in the thorax
Describe the shape & structure of the heart
Conical shape
Wide base - above narrower apex
Ventricular septum separates right & left valves
Upper chambers (=atria) where blood arrives
Lower chambers (=ventricles) pump blood out of heart into arteries
Wall of heart (=myocardium) MUO cardiac muscle tissue
Which muscle is thicker? Left or right of heart? Why?
Left: generates enough pressure to pump blood all around body
Name of double-layered serous sac?
Pericardium
What is the fluid found in pericardium?
Pericardium fluid
What is the pericardium?
Double-layered serous sac surrounding heart
How is back flow back from ventricles to atria prevented?
Atrioventricular valves (tricuspid on right and mitral on left)
What stops the atrioventricular valves everting (flipping inside out) when ventricles contract?
They are attached to the walls of ventricle by fibrous threads (aka chordae tendineae)
When the ventricles relax, what prevents back-flow of blood from the major arteries into the ventricles?
There are semi-lunar valves in the pulmonary artery (pulmonic valve) and aorta (aortic valve) which prevent back-flow to the ventricles.
How are the heart sounds generated?
Closure of the valves within the heart.
When the ventricles contract, the atrioventricular valves close generating the first heart sound, known as lub.
When the ventricles relax, the semilunar valves close generating the second heart sound, known as dub.
Blood flowing from the heart around the body and back to the heart is said to be in which circulation?
Systemic circulation
Blood flowing from the heart to the lungs and back to the heart is said to be in which circulation?
Pulmonary circulation
When the right ventricle contracts, it pumps blood to the …… via the ……
lungs
pulmonary artery
When the left ventricle contracts, it pumps blood to the …….. via the ………
body
aorta
Both the atria contract at the same time and both of the ventricles contract at the same time. When the ventricles are contracted, this period is referred to as ……….. When the ventricles are relaxed, this period is referred to as ……….
systole
diastole
The heart beat is generated by an electrical impulse which begins at the …………………… located in the ……………………..
sinoatrial node
wall of the right atrium
This wave of electrical energy causes the atria to …………. This wave of electrical energy must now pass to a second structure called the ………………….. which is located at the top of the ……………………….
contract
Atrioventricular Node
Interventricular Septum.
The impulse crosses this through a series of fibres called the ……………………..
At the base of the ……………………………….are branches of fibres known as …………..which spread through the ventricular muscle.
Bundle of His
Interventricular septum
Purkinje Fibres
Being arranged in this way ensures that contraction of the ventricles starts at the apex of the heart pushing blood up towards the ………….. and …………………….
pulmonary artery
the aorta.
The myocardium is the muscle of the heart wall. How is this muscle supplied with oxygenated blood?
From coronary arteries (specialised vessels on the surface of the heart)
Why is the cardiovascular system referred to as a double circulation?
Because there is a systemic circulation transferring blood from the heart around the body and back to the heart, whilst there is also a pulmonary circulation transferring blood from the heart, to the lungs and back to the heart.
Blood vessels which carry blood away from the heart are known as ………….. They are thick walled because they …………………………………
arteries
carry blood at high pressure.
Describe the structure of the wall of an artery
The wall of the artery has 3 layers.
The inner layer is a layer of epithelium known as endothelium.
The middle layer consists of smooth muscle and elastic tissue.
The outer layer is a coat of fibrous tissue which gives the vessel strength.
Describe the function of arterioles.
To control blood flow to the capillary beds.
Blood vessels which carry blood towards the heart are known as …………..They are thinned wall because they carry blood which is at
……………. Their structure is similar to that of arteries but they have fewer …………… and …………………..
veins
lower pressure
smooth muscle
elastic fibres.
Describe how blood is moved through veins and how back flow of blood is prevented in veins.
Skeletal muscle contract and press on the walls of the veins pushing the blood along within the veins.
Semi lunar valves prevent back flow
Describe the function of venules
They collect deoxygenated blood from the capillary beds and return it to the heart via the veins.
What is the function of pulmonary artery?
Carries deoxygenated blood from the heart to the lungs
What is the function of pulmonary vein?
Carried oxygenated blood from the lungs to the heart
What is the function of aorta?
Carries oxygenated blood from heart to rest of the body
What is the function of vena cava?
Carries deoxygenated blood from rest of the body back to the heart
What is the function of femoral artery?
Carries oxygenated blood (from aorta) to hindlimb
What is the function of cephalic vein?
Carries deoxygenated blood from forelimb back towards heart (via several other larger veins)
Describe the structure of capillaries?
- Connect the arterioles and the venules across capillary beds
- Thin wall for gas, nutrient and metabolic waste exchange by diffusion.
Blood has roles in both transport and regulation: Describe four substances transported by blood
- Gases – Blood transports oxygen to the tissues from the lungs and carbon dioxide to the lungs from the tissues.
- Nutrients – amino acids, fatty acids and glucose
- Metabolic Waste – transports waste products to the liver and kidneys
- Hormones and Enzymes
Describe four regulatory roles of blood
- Body Temperature – conduct heat from core to periphery
- Acid-Base Balance – a constant internal pH is maintained
- Defence / Immunity – white blood cells and antibodies
- Blood clotting
- Transport o2 and nutrients to organs and tissues
Briefly describe the composition of blood
- Blood is made up of: fluid part (55%) and solid part (45%)
- Plasma is 90% water and rest is plasma proteins, mineral salts, nutrients, dissolved gases and waste products
- The solid part:
o Erythrocytes: carrying oxygen
o Leukocytes: immunity
o Thrombocytes: blood clotting
Describe the structure and function of the erythrocyte
Structure
- Biconcaved circular discs
- Contains haemoglobin and iron
- No nucleus
Function:
- oxygen (oxyhaemoglobin) +some CO2
- most co2 = dissolved in plasma
How is carbon dioxide transported in the blood from the tissues to the lungs?
Carbon dioxide is mainly dissolved in the plasma, with a small amount also bound to haemoglobin in the red cells.
Leukocytes can be ….
granulocytes or agranulocytes
Granulocytes can be…
Basophils
Eosinophils
Neutrophils
Agranulocytes
Lymphocytes
Monocytes
Function of leukocytes
Defend the body against infection
Function of neutrophils
Engulf invading organisms by the process of phagocytosis
Function of eosinophils
Block histamine release (inflammatory response)
Control infections from parasites
Function of basophils
Secrete histamine (increase inflammation)
Release heparin (prevent blood clotting)
Function of lymphocytes
2 forms:
- B-Lymphocytes produce antibodies
- T-Lymphocytes are involved with cell-mediated immunity
Function of monocyte
Become macrophages (remove invading organisms by phagocytosis)
Platelets (or thrombocytes) are fragments of larger cells known as megakaryocytes. What is the function of platelets?
Blood clotting process
Describe the layers around the heart starting from the inside
Endocardium
Myocardium
Epicardium
Pericardial cavity
Parietal layer of serous pericardium
Fibrous pericardium
Describe the steps of pulmonary circulation? (8)
Right ventricle
Pulmonary Semilunar valve
Pulmonary arteries
Lungs
Pulmonary veins
Left atrium
Mitral valve
Left ventricle
Describe the steps of the systemic circulation (8)
Left ventricle
Aortic Semilunar valve
Aorta
Rest of the body
Superior vena cava & inferior vena cava
Right atrium
Tricuspid valve
Right ventricle
How big are capillary walls?
One cell thick
