Circulatory System Flashcards
Heart Sounds
“Lubb” - tricuspid and bicuspid valves closing
“Dupp” - semilunar valves closing
Inflammatory Response
- Mast cells release histamine and heparin into intercellular fluid
- Histamine increases blood flow and increases capillary permeability
- Heparin prevents clotting
- Heat, redness and swelling
- Phagocytes clear debris
- Pain receptors are triggered
The Cardiac Cycle
- Atrial and ventricular diastole
- Atrial systole
- Ventricular systole
Pathogens
Microbes capable of causing disease
- bacteria
- viruses
- fungi
- parasites
Blood pressure
The force with which the fluid in the vessels pushes on the vessels wall
First line of defense
skin; impervious barrier
mucous; traps pathogens
secretion; acidity inhibits entrance
Stroke volume
volume of blood forced from ventricle with each contration
Cardiac output
the amount of blood leaving the ventricles at a time
Vasoconstriction
muscle in the artery constricting to reduce blood flow
Vasodilation
widening of the arteries to increase blood flow
Elements of heart rate control
Adrenaline, medulla, sino-atrial node, atrio-ventricular node
Adrenaline
A hormone that increase the rate and force of heart beats
Causes vasodilation of skeletal muscles and vasoconstriction of peripheral and organ blood vessels
Medulla
Controls the cardiac centre and vasomotor centre parts of the brain
Cardiac centre
relays messages to the SA node and manages the speed of the heart
Vasomotor centre
Controls vasodilation and vasoconstriction
Sino-atrial node
Rhythmically causes depolarisation of neurons causing atrial systole
Also relays info to the A/V node
Atrio-ventricular node
Produces depolarisation of neurons causing ventricular systole
Blood Components
All produced by red bone marrow
Plasma - water, Na+, Ca+, amino acids, hormones, urea
Erythrocytes - 5 mill per ml, survives for 120 days
Leucocytes - 6000-7000 per ml, protects body from pathogens
Thrombocytes - only lasts a week (platelets)
Oxygen transport
Blood with high conc of oxyhaemoglobin is found in the arteries (not around the lungs)
RBC transport oxyhaemoglobin; contains haemoglobin, no nucleus, biconcave discs
Blood with low conc of oxyhaemoglobin in found in the veins
Carbon Transport
8% dissolved in plasma
70% bicarbonate ions
22% carbominohaemoglobin
Coagulation
Damaged cells of blood vessels release adenosine diphosphate - attracts platelets
Grouped platelets form platelet plug
Platelets contact exposed collagen; release more ADP, serotonin and platelet factors
Thrombin converts fibrinogen to fibrin (insoluble)
Fibrin forms a clot
Intracellular fluid
Fluid inside the cells
64% of fluid in blood
Intercellular fluid
Fluid between the cells
Excess is collected by lymph vessels
Extracellular fluid
Outside of the cells
eg plasma
Lymph nodes
Site of filtration
Located along the length of the lymph vessels
Phagocytosis
Macrophages engulf particle, surrounds the particle with projections which force the particle into the microphages, and the particle is digested in 10-30mins
Inflammatory response
1.
Lymphatic System
Blind ended tubules that collect excess intercellular fluid and prevent the spread of pathogens through filtration
Lymph is filtered by lymph nodes
Rejoins the blood stream at the vena cava
