HUBS192 Lecture 13 - Composition and General Functions of Blood Flashcards Preview

HUBS192 Lectures 1-38 > HUBS192 Lecture 13 - Composition and General Functions of Blood > Flashcards

Flashcards in HUBS192 Lecture 13 - Composition and General Functions of Blood Deck (36)
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1
Q

what are the general functions of blood?

A

1) transport
2) immune response
3) coagulation

2
Q

what does the blood transport?

A
  • O2, water, nutrients
  • CO2, waste products
  • ions associated with pH and homeostasis
  • heat
  • hormones
  • immune cells and coagulation factors
3
Q

how does the blood help with the immune response?

A

helps for fighting infection and production of the immune response
-largely done via white blood cells

4
Q

how and why does the blood coagulate?

A
  • to prevent bleeding

- via platelets and “coagulation factors” in plasma

5
Q

what is blood volume proportional to?

A

blood volume is typically in proportion to lean body mass

6
Q

what is the composition of blood?

A

1) plasma

2) formed elements

7
Q

what is the approximate amount of plasma within blood in percentage?

A

55% (with a range of 46-63%)

8
Q

what is the main component of plasma?

A

water makes up over 90% of plasma

9
Q

what are the 3 components of plasma?

A

1) water
2) plasma proteins
3) other solutes

10
Q

what are platelets?

A

cell fragments that participate in clotting to stop bleeding

11
Q

what are the 3 formed elements of the blood?

A

1) platelets
2) white blood cells
3) red blood cells

12
Q

what is the function of white blood cells?

A

immune response and defence mechanisms that seek and destroy invading pathogens

13
Q

what is the function of red blood cells?

A

highly specialised cell that transports oxygen

-most common cell type

14
Q

what is hematopoiesis?

A

the formation of blood cells

15
Q

where is hematopoiesis initiated?

A

initiated in red bone marrow, with contains hemocytoblasts

16
Q

what are hemocytoblasts?

A

progenitors (origin) for all blood cells

17
Q

where are hemocytoblasts located?

A

located in the red bone marrow

18
Q

what is the signal that causes hemocytoblasts to differentiate into red blood cells?

A

stimulated by erythropoietin (EPO)

19
Q

what is another name for a red blood cell?

A

erythrocyte

20
Q

what is the shape of a red blood cell?

A

biconcave disc shape

21
Q

what is the function of red blood cells?

A

allows for efficient diffusion of gases (eg oxygen)

22
Q

what are 2 features of red blood cells?

A

1) large surface area to volume ratio

2) flexibility for movement through narrow capilaries

23
Q

what does a red blood cell contain a large amount of?

A

contains a large amount of haemoglobin (1/3) that uses iron as part of the heme structures to bind O2

24
Q

how many heme units does a red blood cell contain?

A

four heme units, so each haemoglobin can bind four oxygens

25
Q

what is a hematocrits or packed cell volume (PCV)?

A

the fraction of blood occupied by the red blood cells (determined by centrifuged blood separates into its main components

26
Q

what is the relationship between the haematocrit and the amount of exercise a person does?

A

a person who trains frequently will have a higher haematocrit number because they require more oxygen (more red blood cells)

27
Q

what is the haematocrit range for men?

A

0.40-0.54

28
Q

what is the haematocrit range for women?

A

0.37-0.47

29
Q

what is the name for a low haematocrit level?

A

anaemic

30
Q

what is the name for a high haematocrit level?

A

polycythemic

31
Q

what is the process of the generation of red blood cells?

A
  • all blood cells derived from a common progenitor cell= hemocytoblasts
  • RBC production stimulated by erythropoietin (EPO)
  • requires iron to make haemoglobin
32
Q

what is the process of erythropoiesis at high altitudes?

A

reduction in RBCs causes a decrease in O2 delivery - sensed by the kidneys and then erythropoietin is released into the system stimulating the hemocytoblasts to make more RBCs that means more haemoglobin and more haemoglobin means more oxygen can be diffused from the lungs

33
Q

why do athletes train at high altitudes?

A

at high altitude there is less oxygen in the air therefore the body is effectively tricked into releasing more EPO and making more blood cells, therefore when performing at the normal altitudes they will have a larger oxygen carrying capacity

34
Q

what is the process of increasing performance for sport?

A

erythropoietin –> erythrocytes (red blood cells) –> increased O2 capacity –> increased performance

35
Q

what is EPO augmented by?

A

augmented by testosterone

-testosterone is a hormone that stimulates the erythropoietin (EPO) production

36
Q

what is the precursor cell for platelets?

A

megakaryocytes

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