Cardiovascular System Flashcards by Joel Dent

what are the main components of the cardiovascular system?

blood vessels
blood
heart

How well did you know this?

Not at all

Perfectly

what is the cardiovascular system?

A series of tubes: The blood vessels
Filled with fluid: Blood
Closed system
Connected to a pump: Heart
Pulmonary and systemic circulatory systems

How well did you know this?

Not at all

Perfectly

what is the main overview of the cardiovascular system?

Pressure generated in the heart propels blood through the system continuously
The blood picks up oxygen(lungs), nutrients (GI) and deliver these to the body cells.
Simultaneously remove cellular wastes for excretion (liver/renal system)

How well did you know this?

Not at all

Perfectly

what is the primary function of the cardiovascular system?

The transport of materials to and from all parts of the body.

How well did you know this?

Not at all

Perfectly

Why does the blood only flow in one direction?

The valves in the heart and veins prevent the backflow of blood

How well did you know this?

Not at all

Perfectly

How does the blood pressure change around the body?

Flows down a pressure gradient
Highest at the heart (driving P), decreases over distance
Hydrostatic pressure in vessels
Decreases 90% from aorta to vena cava because of friction which causes resistance

How well did you know this?

Not at all

Perfectly

what is the heart composed of?

myocardium

How well did you know this?

Not at all

Perfectly

Which side of the heart has bicuspid AV valves and which has tricuspid AV valves?

Right side has tricuspid
Left side has bicuspid

How well did you know this?

Not at all

Perfectly

What is the name of the valves between the heart and the blood vessels?

semilunar

How well did you know this?

Not at all

Perfectly

What is the name of the left AV valve?

mitral valve

How well did you know this?

Not at all

Perfectly

What is the gap between the heart and the fibrous pericardium called?

The pericardial cavity

How well did you know this?

Not at all

Perfectly

List some coronary arteries

*Left/right coronary artery
*Right (acute) marginal artery
*Left (obtuse) marginal artery
*Posterior descending artery

How well did you know this?

Not at all

Perfectly

What are the cardiac cells and their function?

Myocardial cells Bulk of the heart
* Contractile cells – mechanical force

Pacemaker cells (autorhythmic cells) 1%
* Spontaneous action potentials – coordinate contraction
* No contribution to mechanical force Action potentials (pacemakers) – excitation myocardium – contraction(Excitation-Contraction coupling)

How well did you know this?

Not at all

Perfectly

Describe the electrical conduction in the heart

*SA node produces an action potential which travels through the atria causing contraction.
*Action potential reaches AV node which sends potential down the bundle of His to the purkinje fibres.
*This causes the ventricles to contract.

How well did you know this?

Not at all

Perfectly

Describe excitation-contraction coupling (EEC)

Impulse arrives at the muscle cell membrane- in the form of electric current (Action Potential)
Plasma membrane is depolarized subsequently leading to cellular depolarization.
Depolarization spreads to T-tubules in muscle(cardiac, skeletal) generating a contraction (Ca2+wave)

How well did you know this?

Not at all

Perfectly

What are the phases of myocardial cell action potential?

*Phase 4: Resting membrane potential. *Phase 0: Depolarization.
Voltage-gated Na+ channels opens generating an inward Na+ current .
*Phase 1: Initial repolarization.
Na+ channels close. K+ channels opens. Outward K+ current
*Phase 2: Plateau.
Two events:
1) decrease in K+ permeability (smaller outward current)
2) Ca+ inward current
*Phase 3: Repolarization.
Ca+ channels close and K+ channels opens (again).Outward K+ current. Causes a prolonged refractory period.

How well did you know this?

Not at all

Perfectly

Why is there a long refectory period in cardiac muscle?

To prevent a prolonged contraction, meaning no blood gets pumped.

Why does the pacemaker action potential have an unstable action potential?

Due to If, (funny current):
1) Na+ inward current (first)
2) Ca2+ inward current (later

what does P-Wave stand for?

atria depolarise

What is the QRS wave?

ventricles depolarize, (atria repolarize)

What is the T-wave?

ventricles repolarise

What is gained from an ECG?

(Non-invasive)
Heart Rate
Signal conduction
Heart tissue
Conditions

What are arteries?

*Transport blood from heart
* Strong & Elastic
* Conduct blood to capillaries

What is the function of capillaries?

exchange with cells

What is the function of veins?

* Return blood to heart * Valves

What are the layers in an artery?

*Endothelium *Smooth muscle cell layer *Adventitia

What are the layers in blood vessels (except capillaries)?

* Inner layer: Tunica interna (intima) * Middle layer: Tunica media * Outer layer: tunica externa

What is the innermost layer of vessels (tunica interna) comprised of?

1) Endothelial cells. * Controls contractility –secreting endothelial factors(paracrine) that mediate contraction/dilatation 2) Basement Membrane separates the tunica intima from the tunica media 3) In arteries, a layer of elastic tissue called the internal elastic lamina (allows distension when high pressure blood is ejected from the ventricles)

What is the middle layer of vessels (tunica media) comprised of?

* Smooth Muscle Cells- maintains a partial contraction (sets vascular tone).Contraction triggered byCa2+ entry. Paracrine regulation of their contraction/relaxation by the endothelial cells * Gap junctions (transmission of action potentials) * Elastin (elastic) fibre

What is the outermost layer of vessels (tunica externa) comprised of?

* Collagen and Elastin fibres * elastic tissue (external elastic lamina). * Vasa vasorum (vessels of the vessel):capillaries in large arteries and veins that provide oxygen and nutrients to the cells in the tunica externa

Describe the red blood cells

Erythrocytes Concave shaped cells Anucleated Contain Haemoglobin Most abundant cells in body Account for 40-45% of blood volume Develop in bone marrow Last 120 days then broken down and recycled by macrophages

Describe haemoglobin

* Protein responsible for transporting oxygen in the blood of vertebrates * Comprises four subunits (2alpha and 2 beta) * Each subunit contains an iron atom bound to a haem group * Each haem can bind an oxygen molecule

What is the effect of oxygen on haemoglobin?

*When oxygenated it becomes a more relaxed structure and has a higher affinity for oxygen *When deoxygenated it becomes tense and has a lower affinity for oxygen

How is carbon dioxide transported in the blood?

Bicarbonate major. ~85% In solution ~ 5% Bound to Hb ~10%

What increases the rate of production of red blood cells in response to falling levels of oxygen in the tissues?

Glycoprotein hormone secreted by the kidneys

What causes jaundice?

Increased bilirubin

What are the different types of anaemia?

*Iron deficiency anaemia – diet/haemorrhage *Thalassemia – genetic disorder; alpha or beta forms(Alpha or beta globulin absent/faulty) *Aplastic anaemia *Sickle cell anaemia *Vitamin deficiency anaemia – pernicious anaemia

What is the causes of aplastic anaemia (body does not produce blood cells)?

* Autoimmune disorders * Toxic substances * Chemotherapy * Viral infection * Certain medications including some antibiotics * Cancer that affects has spread to the bone marrow * Inherited conditions

What causes sickle cell disease?

A group of inherited conditions of sickle haemoglobin. Abnormal beta-globin chain which causes it to polymerize when deoxygenated distorting the erythrocyte into a sickle shape.

What are some types of white blood cells?

Granulocyte: WBCs with granules in their cytoplasm neutrophil, eosinophil, and basophil. Agranulocytes: WBCs with no distinct granules in their cytoplasm. monocyte (macrophages) and lymphocyte.

How are blood clots formed?

*Injury to vessel lining triggers the release of clotting factors. *Vasodilation limits the blood flow and platelets form a sticky plug. *Fibrin strands adhere to the plug to form an insoluble clot

What are platelets activated by?

* ADP * Thromboxane A2 * Thrombin * Serotonin