week 8- cardiovascular

Question 1

what are the 3 functions of blood

Answer 1

transportation
regulation
protection

Question 2

what does the blood transport

Answer 2

function of blood is to deliver oxygen and nutrients to, and remove wastes from body tissues and cells. It transports;
-oxygen from the lungs to cells
-carbon dioxide from cells to the lungs for exhalation
-nutrients from the gastrointestinal tract to cells
-hormones from endocrine glands to target cells
-drugs from the site on absorption to target cells and tissues
-cellular wastes and byproducts products to the kidneys for excretion.

Question 3

regulation of blood involves what

Answer 3

Blood helps maintain homeostasis of all body fluids. For example;
- proteins and chemicals in blood act as pH buffers (convert strong acids or bases into weak ones), therefore help to regulate the pH of body fluids and cells
- blood osmotic pressure helps regulate the water content of body cells, mainly though interactions of dissolved ions and proteins.
- Blood also helps adjust body temperature via a negative feedback loop

Question 4

blood protection involves what

Answer 4

White blood cells protect against;
- external threats, such as bacterial pathogens
- internal threats, such as cells with mutated DNA that could become cancerous, or body cells infected with viruses.
-Blood can clot, which protects against excessive blood loss and initiates the healing process

Question 5

what is the pH of blood

Answer 5

pH: 7.35 - 7.45

Question 6

what tissue type is blood

Answer 6

connective tissue

Question 7

what temp is blood

Answer 7

38 degrees

Question 8

what is bloods viscosity in relation to water

Answer 8

5x thicker

Question 9

what is the colour of blood

Answer 9

Colour: varies with its oxygen content. Bright red when oxygenated, dark red when deoxygenated

Question 10

what is the volume of blood

Answer 10

Volume: about 8% of adult body weight.

Question 11

Composition of blood

Answer 11

Whole blood has two components; blood plasma (liquid extracellular matrix) and formed elements (cells and cell fragments).

Question 12

what are the components of blood plasma

Answer 12

91.5% water
7% proteins
1.5% other solute

Question 13

what are the 3 main groups of plasma

Answer 13

Albumin, Globulins, Fibrinogen

Question 14

Albumin (54-60%);

Answer 14

• made by the liver
  -transport vehicle for fatty acids, calcium and steroid hormones
  -contributes to osmotic pressure of blood - helps draw water from the tissues, across the blood vessel walls, and into the blood stream.

Question 15

Globulins (35-38%);

Answer 15

-immunoglobulins (antibodies) - made by plasma cells, bind to specific antigens and mark them for destruction by specialised white blood cells
-alpha and beta globulins - made by the liver, transport iron, lipids, and the fat-soluble vitamins A, D, E, and K to the cells, they also contribute to osmotic pressure.

Question 16

Fibrinogen (4-7%)

Answer 16

• made by the liver
• essential for blood clotting - form clots and produce long, insoluble strands of fibrin.

Question 17

RBC/Erythrocytes characteristics

Answer 17

• No nucleus - therefore cannot repair
• No mitochondria - therefore they rely on anaerobic respiration of glucose
  -No endoplasmic reticulum - therefore they do not synthesise proteins
• Have structural proteins - helps maintain their structure and enables them to change shape to fit in capillaries
  -Biconcave disks - plump at their periphery and very thin in the centre. this provides a greater surface area for gas exchange and enables them to fold up as they move through narrow blood vessels

Question 18

Haemoglobin

Answer 18

Haemoglobin is a large molecule made up of four globin proteins, each of which is bound to one molecule of the iron-containing pigment haem, which contains an ion of iron (Fe2+). Each iron ion in the haem can bind to one oxygen molecule; therefore, each haemoglobin molecule can transport four oxygen molecules

Question 19

vascular spasm

Answer 19

Damage to the blood vessel triggers contraction of the smooth muscle in the vessel wall. This local contraction narrows the vessel lumen at the site of injury resulting in a decrease in blood flow to the area

triggered by: endothelins

Question 20

platelet plug formation

Answer 20

begins when platelets bind to the exposed collagen at the site of blood vessel damage, and become activated. Activated platelets bind to other platelets and the endothelial lining forming a platelet plug.

Question 21

coagulation

Answer 21

Coagulation (blood clotting) is a complex cascade of enzymatic reactions resulting in the conversion of fibrinogen (a soluble protein) into fibrin (an insoluble protein). As the fibrin mesh gorws, plateletes and blood cells are trapped, forming a clot that seals off the damaged vessel.

Question 22

what are the 3 different clotting pathways

Answer 22

Extrinsic pathway Intrinsic pathway
Common pathway

Question 23

extrinsic pathways

Answer 23

• triggered when clotting factors outside the blood vessel leak into blood
• fewer steps (compared to intrinsic pathway)
• begins within seconds
  -damaged cells releae tissue factor (TF)
  -activates Factor X which combines with factor V in the presence of calcium to form prothrombinase

Question 24

insintric pathways

Answer 24

• triggered when clotting factors come into contact with substances inside the blood vessel
• mors steps (compared to extrinsic pathway)
  -takes minutes to begin
  -begins with circulating proenzymes
  -platelets relases factors (e.g. PF-3)
  -activates Factor X which combines with factor V in the presence of calcium to form prothrombinase

Question 25

common pathways

Answer 25

• where extrinsic and intrinsic pathways converge
• prothrombinase (and calcium) converts prothrombin into thrombin
• thrombin (and calcium) converts fibriogen into fibrin
• fibrin forms the threads of the clot

Question 26

clot retraction

Answer 26

The contractile proteins within platelets within the clot, undergo contraction. This pulls the fibrin threads, bringing the edges of the clot more closer together; which

• decreases the size of the damaged area
• decreases the residual bleeding and stabilises the injury
• permits healing.

Question 27

fibrinolysis

Answer 27

To restore normal blood flow as the vessel heals, the clot must eventually be removed. Fibrinolyisis is the slow process by which the clot is degraded;

• thrombin and tissue plasminogen activator (t-PA) activate plasminogen
• plasminogen produces plasmin
• plasmin digests fibrin strands.

Question 28

Rhesus system

Answer 28

Rhesus (positive or negative) blood types are classified according to the presence or absence of the D surface antigen.

Question 29

ABO system

Answer 29

ABO blood types are classified according to the presence or absence of two antigens, A and B, on the RBC surface