week 7

Question 1

Blood vessels (what they transport)

Answer 1

Transport:

• essential nutrients towards cells
• wastes away from cells
• regulating molecules to/from cells
• dissipation of heat
• cells & chemicals for protection/ defence

Question 2

Blood vessels (how they transport)

Answer 2

Exchange of materials between blood & tissues

Question 3

Maintaining one way flow (list 3)

Answer 3

Valve:
- prevent back flow

Skeletal muscle pump
- massaging effect of muscle movement on the veins and assisting in blood flow up

Respiratory pump
- breathing in decreases pressure in the chest allowing blood to flow up more easily

Question 4

Blood flow

Answer 4

Blood volume through a vessel within a given time period

Pressure difference = hight -> low

Question 5

Blood flow resistance

Answer 5

Flow decreases as resistance increases

• vessel diameter
• vessel length
• blood viscosity

Question 6

Capillary Osmotic pressure (OPc)

Answer 6

• force opposing hydrostatic pressure

- mainly due to plasma proteins

Question 7

Capillary Hydrostatic pressure (HPc)

Answer 7

force exerted by fluid pressing against a wall

Question 8

Net movement

Answer 8

Fluids will leave capillary if net HPc is greater than OPc
- OUT>IN

Fluids will enter capillary if net OPc is greater than HPc
- IN>OUT

Question 9

Capillary exchange (3 types)

Answer 9

Diffusion:

• water, ions and small molecules
• some ions (Na+, K+, Ca2+, Cl-) through channels

Filtration

• driven by hydrostatic pressure
• determined by size

Reabsorption
- driven by blood colloid osmotic pressure

Question 10

HR

Answer 10

Heart Rate = beats per minute

Question 11

SV

Answer 11

Stroke Volume = mL per beat

Question 12

CO

Answer 12

Cardiac Output = mL per minute

Question 13

Systolic BP

Answer 13

pressure exerted against vessel at contraction

• Identified as top number

Question 14

Diastolic BP

Answer 14

pressure exerted at against vessel at relaxation.

• Identified as bottom number.

Question 15

Pulse Pressure

Answer 15

difference between SBP & DBP.

Question 16

Mean Arterial Pressure (MAP)

Answer 16

average arterial blood pressure

S + D + D
\_\_\_\_\_\_\_
      3
s - systolic
d - diastolic

(Over 60 = good)

Question 17

Stroke volume (3 parts)

Answer 17

Preload
• Stretch in muscle fibres
• More stretch… more strength….. to a limit

Afterload
• Pressure needed to open SL valves -> eject blood.

Contractility
• Force of contraction

Question 18

2 Parts of ANS of the heart

Answer 18

SNS
increase Heart rate (chronotropic)
increase Contractility (inotropic)

PSNS
decrease Heart rate
decrease Contractility

Question 19

Regulation of heart rate (2 components)

Answer 19

Internal
- Cardiac conduction system

External control

• Medulla oblongata
• Centres

Question 20

Antagonistic control ( 2 centers)

Answer 20

Cardioacceleratory

Cardioinhibitory

Question 21

Function of blood

Answer 21

Transport 
•oxygen,nutrients,waste,hormones, drugs
•Regulation of pH and ions 
•body temperature, pH, fluid volume
•Protection 
•blood loss, infection

Question 22

Composition of blood

Answer 22

1. Plasma (fluid)
   •water plus proteins
   •carries nutrients,hormones, gases,wastes and electrolytes
2. Regulation of pH and ions
   •RBC, WBC, platelets
   •all formedinbone marrow (stem cells)

Question 23

Red blood cells + haemoglobin

Answer 23

• makes blood red

* binds and transports oxygen and carbon dioxide

Question 24

Haemoglobin structure and function

Answer 24

Iron binds oxygen
•Oxyhaemoglobin
•deoxyhaemoglobin

Protein binds CO2
•carbaminohaemoglobin

Question 25

RBC structure and function

Answer 25

* High surface to volume ratio * quickly absorbs and releases oxygen * Discs form stacks (roleau) * smooth flow through narrow blood vessels * Discs bend and flex entering small capillaries * 7.8µm RBC passes through 4 µm capillary

Question 26

White blood cells (leukocytes)

Answer 26

* No haemoglobin (not red) * Have nuclei and other organelles * Live hours-years * Five different types WBC functions •defend against pathogens •remove toxins and wastes •attack abnormal cell

Question 27

Five types of leukocytes

Answer 27

Neutrophil - Phagocytic -bacteria (40-70% WBC) Eosinophil - increase in allergic reactions and parasitic infections (1-4% WBC) Basophil - Release histamine and contain heparin (0.5-1% WBC) Lymphocyte - B cells, T cells &NK cells (20-45% WBC) Macrophage - AKA monocytes –enter tissues to become macrophages (4-8% WBC)

Question 28

Platelets (thrombocytes)

Answer 28

* Fragments of very big cells (megakaryocytes) * Circulate 9-12 days * Removed by spleen * 2/3 reserved for emergencies

Question 29

Platelets –three functions

Answer 29

* Release important clotting chemicals * Temporarily patch damaged vessel walls * Reduce size of break in vessel wall

Question 30

Haemostasis

Answer 30

Cessation of bleeding Three phases - Vascular phase - Platelet phase - Coagulation phase

Question 31

Vascular phase

Answer 31

Immediate vasoconstriction: 1. contract & expose basement membrane 2. Release chemicals •inc.vWF–platelets to collagen •Stimulate smooth muscle contraction 3. Endothelium become “sticky” •Seal off blood flow

Question 32

Platelet phase

Answer 32

Begins to seal damaged vessel Platelet adhesion •chemicals from damaged tissue •platelets become sticky Platelet aggregation •release chemotactic substances •forms plateletplug

Question 33

Coagulation phase

Answer 33

``` Begins ~30 sec after injury •Blood clotting = coagulation •Liquid blood forms gel •Cascade of reactions (dominoes) •End result = conversion of fibrinogen into fibrin ```

Question 34

Clot retraction

Answer 34

* Final step * Platelets pull on fibrin –threads contract * Pulls torn edges of vessel closer together * reducing bleeding & stabilising injury site * Reduces size of damaged area •makes repair easier

Question 35

Blood typing + surface antigens

Answer 35

Surface antigens •cell surface proteins that identify cells to immune system •normal cells are ignored and foreign cells attacked Blood types •genetically determined •by presence/absence of RBC surface antigens A, B, Rh (or D)

Question 36

Cross-reactions in transfusions

Answer 36

* AKA transfusion reactions * Plasma antibody meets its specific surface antigen •Blood will agglutinate (clump) and haemolyse * Occurs if donor and recipient blood types incompatible