Blood, Vessels And Disorders

Question 1

Arteries and arterioles
(A for away)

Answer 1

• take blood Away from heart
• carry oxygenated blood except pulmonary artery that takes deoxygenated blood away from heart to lungs
• blood comes directly from heart under high pressure
• have thick muscular walls
• must stretch to accommodate pressure, average is 100 mmHg
• pulse: caused by stretching of artery wall with each heartbeat

Question 2

Capillaries
(C for connect)

Answer 2

• connect arteries to veins
• network of tiny vessels
• very thin lace like walls (one cell thick) to:
- allow exchange of nutrients and wastes between blood & cells
- very narrow to: slow blood down to give time for diffusion
- RBCs must pass one at a time, bend to get through

Question 3

Veins and venules
(V for venir)

Answer 3

• return blood from body to heart
• carry deoxygenated blood (exception) pulmonary vein (from lungs to heart high o2)
• low blood pressure (90 mmHg)
- ( slowed down in capillaries)
• have less muscular walls
• need valves to prevent backflow
• blood is moved along by: skeletal muscular contraction

Question 4

Control of blood vessels

Answer 4

• controlled by involuntary muscles (smooth) muscles
• vasoconstriction
- closing or narrowing of blood vessels, less blood is delivered to tissues
- increases b.p. ex cold (pale)
• vasodilation
- opening or expanding of blood vessels! More blood is delivered to tissues
- decreases b.p. ex hot (flushed) or blush

Question 5

Control of blood vessels

Answer 5

• controlled by involuntary muscles (smooth) muscles
• vasoconstriction
- closing or narrowing of blood vessels, less blood is delivered to tissues
- increases b.p. ex cold (pale)
• vasodilation
- opening or expanding of blood vessels! More blood is delivered to tissues
- decreases b.p. ex hot (flushed) or blush

Question 6

Blood

Answer 6

• blood volume (average adult) 7% of body weight
- males: 5 to 6 litres
- females: 4 to 5 litres
• slightly alkaline, pH (7.35 - 7.45)
• composed of:
- 55% plasma: liquid components
- 45% cells: solid components
• blood cells: 3 different kinds produced by stem cell in the bone marrow

Question 7

Plasma

Answer 7

yellowish liquid suspension. contains 90% h2o, dissolved solutes, and proteins