Lecture 6 - Circulatory system

Question 1

Plasma: what is it and what is it comprised of?

Answer 1

Fluid within blood vessels

Contains water, WBCs, platelets, coagulation factors, essential proteins, food etc

Question 2

Interstitial fluid: what is it and how is it produced?

Answer 2

Fluid between cells

At the capillary space nearer to the arteriole, fluid is pushed out into the interstitial fluid

At the capillary space nearer to the venule, fluid is drawn into the capillary from the interstitial fluid

Question 3

Capillary blood pressure: what does it do and what happens with the pressure in the capillary

Answer 3

CBP - Involved in filtration of fluid: high pressure pushes fluid out, low pressure draws fluid in (when in conjunction with BCOP)

Gradually decreases across the capillary

Question 4

Blood colloid osmotic pressure: what does it do and what happens with the pressure in the capillary?

Answer 4

BCOP - pulls fluid back into the capillary by the use of proteins

This remains constant across a capillary, but, as the CBP changes, its effect is more significant at the latter end of the capillary

Question 5

Reabsorption of fluid: how much is reabsorbed and why must the rest be removed?

Answer 5

Approximately 85% of the fluid is reabsorbed, if the rest is not moved away, oedema can occur

Question 6

Lymphatic capillaries: what do they do and what are they?

Answer 6

Pick up the remaining 15% of interstitial fluid pushed out from capillaries

Blind-ended tubes that are adjacent to capillary beds

Question 7

Lymph: what is it and where does it move through?

Answer 7

The name given to excess interstitial fluid

Lymph passes through capillaries to vessels to nodes to trunks to either the thoracic duct or right lymphatic duct

Question 8

Lymphatic drainage: where does it occur and which duct drains which part of the body?

Answer 8

Right lymphatic duct -> right subclavian vein

Thoracic vein -> left subclavian vein

Question 9

Alternate terms:
- armpit - head -neck
- arm -back of the knee
- upper arm bone - top forearm bone - bottom forearm bone - top hip bone
- middle hip bone - bottom hip bone
- thigh bone - anterior calf bone
- knee bone - posterior calf bone
- toe bones - feet bones
- ankle bones - finger bones
- hand bones - collar bone
- shoulder bone - breastbone

Answer 9

⠀
- Axillary fossa - cephalic - jugular
- brachium - popliteal fossa
- humerus - radius
- ulna - ilium
- ischium - pubis
- femur - tibia
- patella - fibula
- phalanges - tarsals/metatarsals
- Talus (+ T & F) - phalanges
- carpals/metacarpals - clavicle
- scapula - sternum

Question 10

Arteries: pathways through the body:
Aortic arch

Answer 10

⠀
Brachiocephalic trunk -> upper right body

Descending Thoracic aorta -> lower body

Left common carotid -> left side of the head

left subclavian -> left arm and shoulder

Question 11

Arteries: pathways through the body:
Brachiocephalic trunk

Answer 11

⠀
Right common carotid -> head

Right subclavian -> arm and shoulder

Question 12

Arteries: pathways through the body:
Right/left subclavian

Answer 12

⠀
Right/left subclavian -> axillary -> brachial -> raidal/ulnar

Question 13

Arteries: pathways through the body:
Descending Thoracic aorta

Answer 13

⠀
dTa -> abdominal aorta -> common iliiac -> external iliac

Question 14

Arteries: pathways through the body:
External iliac

Answer 14

⠀
External iliac -> Internal iliac

External iliac -> femoral -> popliteal -> anterior tibial

Question 15

Six types of circulation within the body

Answer 15

General systemic circulation - supplies blood to the body

Coronary circulation - supplies blood to the heart

Pulmonary circulation - oxygenates the blood

Foetal circulation - skips lungs (ductus arteriosus and foramen ovale) as they don’t oxygenate the blood and liver (ductus venosus) as it is underdeveloped

Portal circulation - blood passes through multiple capillary beds

Lymphatic circulation - moves lymph through the body

Question 16

Portal circulation: what is it, what does it do, and what examples?

Answer 16

Involves blood passing through one capillary bed, and then a portal vein carries blood from that capillary bed directly to another one before circulating back to the heart

This allows the direct movement of materials through the blood

Hypophyseal and hepatic (blood passing through the digestive system gets filtered in the liver before returning to the heart) portal systems

Question 17

Hypophyseal portal system

Answer 17

The portal vein connects the hypothalamus and pituitary gland and allows the hypothalamus to directly give instructions to the pituitary gland

Question 18

Hepatic portal system

Answer 18

The main portal system, the gastrointestinal tract has capillary beds that are connected to a portal vein towards the liver and this allows the processing of digested material.

This contributes to the first pass effect, meaning that some drugs may not reach target organs due to breakdown in the liver because of oral consumption

Question 19

Lymphatic circulation: what does it do and how does it do this?

Answer 19

Moves lymph (fluid) around the body and acts as a drainage system for fluid and a defence mechanism

It drains lymph by capillaries releasing it and being picked up by lymph capillaries

It acts as a defence mechanism by passing lymph through lymph nodes which contain lymphocytes to break down pathogens

Question 20

Lymph nodes

Answer 20

Contains many lymphocytes, and foreign particles are trapped.

The trapped particles may be destroyed by macrophages and immune responses can be triggered