Cardiovascular - Heart Flashcards
Why is it called a double circulatory system?
Because there are two parts - systemic (body) and pulmonary (to and from lungs)
What are the two vena cava’s called?
Inferior and superior
What vessel does blood enter the heart through?
Vena cava
What vessel does blood exit the heart to the lungs?
Pulmonary artery
What vessel does blood exit the heart to the body?
Aorta
What vessel does blood enter the heart from the lungs?
Pulmonary vein
Why is the heart more muscular on the left side?
Because it pumps blood to the body so needs to be pumped stronger
What side of heart is the bicuspid valve found?
Left
What side of heart is the tricuspid valve found?
Right
What type of valves are the aortic and pulmonary valves?
Semi lunar valves
Where is haemoglobin oxygenated?
The lungs
Where is the SA node located?
Top of right atrium
Where is the AV node located?
Bottom of right atrium
What is the role of the SA node?
Makes atria contract at same time
What is the role of the AV node?
Sends signal that delays ventricles from pumping until all blood from atria has entered ventricles
What is the SA node known as?
The pacemaker
What is the structure of the purkinjie fibres?
Very fine, small, specialised fibres
What is the function of the purkinjie fibres?
They transmit impulses from AV node to ventricles
What does the AV septum prevent?
Stops atria and ventricles from pumping at the same time
What does SA node stand for?
Sinoatrial node
What does AV node stand for?
Atrioventricular node
What does the P wave show?
Contraction of atria
What does the QRS wave show?
Contraction of ventricles
What does the T wave show?
Relaxation of ventricles
What does the flat line between P and Q show?
The 0.1 second delay - impulse reaches AV node for delay
What does the downwards line between P and Q show?
The bundle branches carrying signal from AV node to hear apex
What does an ECG show?
Electrical current of the heart
What can an ECG indicate?
Abnormal heart conditions
What are the outside walls of arteries made of?
Smooth muscle
Why are walls of arteries thicker than veins?
Because they need to withstand greater pressure
What do arteries have to stretch and recoil?
Elastin
What do arterioles connect?
Arteries and capillaries
What structure do arterioles have?
They are smaller versions of arteries with muscular walls
What structure do capillaries have?
One cell thick - enables nutrients and gases to pass through
Why do capillaries have low pressure?
So diffusion can occur
What diffuses through capillaries?
Oxygen, carbon dioxide and nutrients
What do venules connect?
Capillaries and veins
Do venules have valves?
No
What size lumen do veins have?
Large
Why do veins have valves?
Prevent backflow of blood
What type of blood do veins carry?
Deoxygenated
What type of blood do arteries carry?
Mostly oxygenated - excludes pulmonary artery
What are the names of vessels to the liver?
Hepatic artery, hepatic vein and portal vein
What are the names of vessels to the kidneys?
Renal artery and renal vein
What is osmosis?
Movement of molecules across a semi-permeable membrane
What diffuses in osmosis?
Oxygen, carbon dioxide, nutrients and waste
Why cant proteins diffuse?
They are too large
What is tissue fluid?
a yellowish liquid made from blood plasma
What does tissue fluid do?
It bathes all cells + acts as transport medium between blood and cells
Supplies nutrients to tissues and receive carbon dioxide and other waste materials from surrounding tissue
What substances are found in tissue fluid?
WBC’s, oxygen, sugars, salts, amino acids and hormones
What is tissue fluid made up of?
Small molecules and water found in plasma
How is tissue fluid made?
Fluid leaves capillaries and enters tissues
What does plasma contain that tissue fluid doesn’t?
Large proteins
What is hydrostatic pressure?
Capillaries are narrower than arterioles so pressure builds up which forces water out of blood plasma
What is osmotic pressure?
Hydrostatic pressure is resisted by the lower water potential of blood caused by blood proteins that are too large to leave capillaries = osmotic pressure
What us ultrafiltration?
Pressure pushes water and small molecules out of capillary leaving cells and large proteins behind
When does osmosis occur in blood?
Capillaries take in water (containing waste) from blood plasma, reducing hydrostatic pressure.
What happens to any remaining tissue fluid?
It enters lymph vessels and goes back to veins
What happens to tissue fluid that doesn’t go back to capillaries?
Enters lymphatic system and forms lymph
What is the lymphatic system made up of?
Lymphatic capillaries, lymph nodes and lymphatic tissue
What are lymphatic capillaries?
Vein-like lymph vessels containing valves
What are lymph nodes?
Sac-like organs that trap pathogens + foreign substances - contain lots of WBC ‘s
Where is lymphatic tissue found?
Spleen, thymus and tonsils
What does lymphatic tissue contain?
Large amounts of WBC’s involved in their development
What is blood made of?
55% water, 45% cells (mostly erythrocytes)
What is serum made up of?
Mainly water, some proteins, ions and nutrients - no fibrinogen
What is lymph made up of?
Mainly water, some small molecules and lipids
What is plasma made up of?
Mainly water - plus proteins, ions, nutrients and waste
What is tissue fluid made up of?
Mainly water - plus small molecules e.g. oxygen
What are the 3 types of blood proteins?
Albumins, globulins and fibrinogen
What is the structure of albumins?
Largest out of 3 proteins and contribute to viscosity of plasma
What do albumins do?
Main contributers to osmotic pressure, allow tissue fluid to move back to capillaries.
What happens if we have a lack of albumins?
Lead to build up of tissue fluid in tissues = oedema
What do globulins do?
Have antibodies and immunoglobulins
They are protective proteins made by lymphocytes that are essential to immune system
What does fibrinogen do?
Helps blood clot
What does lymphatic system do?
Drainage and filtration, remove excess fluid from tissues, absorbs fatty acids and transports to bloodstream to go to small intestine, produces lymphocytes
