DHUBS1 - week 7 Flashcards
(18 cards)
the cardiovascual system consists of?
the heaert
blood vessels
fluid connective tissue (Blood)
functions of blod
- Transport of substances (e.g. gases, waste products, hormones, nutrients)
- Regulation of blood pH and blood ions (e.g. absorbs and neutralises lactic acid)
- Restriction of fluid losses at injury sites (blood clotting)
- Defence against toxins and pathogens (white blood cells)
- Stabilisation of body temperature (absorbs heat form active muscles, distributes to other tissues)
- Maintenance of blood volume (protein(albumin))
4 basic blood types
Type A (surface antigen A) has antibodies to B
Type B (surface antigen B) has antibodies to A
Type AB (surface antigens A and B) neither antibodies
Type O (neither A nor B surface antigens) antigens to A and B
thrombocytes (platelets)
Cell fragments involved in human clotting system
Disc-shaped structures
Circulate for 9-12 dyas
Are removed by spleen
Three functions
1. Release important clotting chemicals
2. Temporarily patch damaged vessel walls
3. Actively contract tissue after clot formation
how body stops bleeding (3 basic steps)
- vascular phase
- platelet phase
- coagulation phase
explain vasuclar phase
Vascular spasm – 30 min
Smooth muscle contracts in damaged vessel
Caused by:
Damage to smooth muscle
Activation of platelets: release of vasoconstrictors
Reflexes initiated by pain receptors
explain platelet phase
Begins within 15sec of injury
Platelet plug formation: where they contact and stick to damaged tissue in vessel wall. The platelets are activated: extend projection and attach to each other, then release clotting compounds.
explain coagulation phase
Begins 30 seconds or more after the injury
Blood clotting (coagulation)
Clotting factors (liver enzymes, platelets) promote formation of prothrombinase
Converts prothrombin into thrombin
Convert circulating fibrinogen into insoluble fibrin
Fibrin forms threads which traps formed elements to make clot
2 circuits of the cardiovascualr system
pulmonary circuit: blood to and from the lungs
systematic circuit: blood to and from all other organ systems
three walls of the heart
called the parietal pericardium cover which consists of
1. Epicardium wall: surrounding the heart
2. Myocardium wall: cardiac muscle
3. Endocardium wall: simple squamous epithelial, lining the heart
heart structure - anterior surface
Pulmonary trunk
Aortic arch
Left atrium
Left ventricle
Right ventricle
Right atrium
Superior vena cava
Ascending aorta
internal heart structure
4 chambers:
- 2 Atria
- 2 Ventricles
4 valves:
- 2 are called atrioventricular valves (AV valves) between atria and ventricles
R- side = tricuspid
L- side = bicuspid (Mitral)
- 2 are called semilunar valves (SL valves)
One at the entrance to lungs = pulmonary valve
One at the base of aorta = aortic valve
vessels that supply blood to the heart muscle
coronary arteries
veins
two types of cardiac muscle cells involved in our heartbeats
myocardial conducting cells: two types - pacemaker cells and cardiac conducting cells
myocardial contractile cells
conduction system pathway in heart
- Sinoatrial (SA) node
- Atrioventricular (AV) node
- AV bundle
- R and L bundle branches
- Purkinje fibres
the cardiac output
the volume of blood pumper out of each ventricle in 1 minute
how to calculate cardiac output
cardiac output (mL/min) = heart rate (beats/min) x stroke volume (mL/beat) (volume of blood pumped out by one ventricel with each beat)
factors the control cardiac output
autonomic nervous system
cirulating hormones
electrolyte imbalances and changes in body temperature can increase/reduce CO
