Lecture 19 - Vascular System Flashcards Preview

BIOM20002 - HSF > Lecture 19 - Vascular System > Flashcards

Flashcards in Lecture 19 - Vascular System Deck (52)
Loading flashcards...
0
Q

What is the innervation of arteries?

A

Vasomotor

Sympathetic innervation that controls the smooth muscle, and thus the diameter of the lumen

1
Q

What is the structure of an artery?

A

Intima: endothelium
Media: smooth muscle
Adventitia: fibrous material

2
Q

What is the major division of the circulatory system?

A

Pulmonary

Systemic

3
Q

Describe blood flow around the heart

A
  1. Venous return via IVC and SVC into right atrium
  2. Right ventricle
  3. Pulmonary artery
  4. Lungs
  5. Pulmonary vein
  6. Left atrium
  7. Left ventricle
  8. Aorta
  9. Body
4
Q

What are the different types of vessels?

A
Arteries
Arterioles
Capillaries
Venules
Veins
Lymphatics
Lymph vessels
5
Q

Describe the flow of lymph around the body

A
  1. Interstitial fluid drains into lymph capillaries
  2. Afferent lymph vessels
  3. Lymph node
  4. Efferent lymph vessel
  5. Lymph duct
  6. Draining back into circulation
6
Q

Why is there a pressure difference in the pulmonary and systemic circulation? What is this difference?

A

Pulmonary: low pressure, because the blood doesn’t have to travel far

Systemic: high pressure, because the blood must travel all around the body

7
Q

Is any part of the body avascular?

A

Yes:
Epidermis
Articular cartilage

8
Q

How may an artery and vein be distinguished when dissecting?

A

Arteries always have a lumen, due to the thick smooth muscle wall

Veins collapse, and there is no visible lumen

9
Q

When does an artery normal branch?

A

At a joint, such as the elbow

10
Q

What are the different branches that an artery can form?

A
Muscular branch
Nutrient branch
Articular
Cutaneous
Arteriae nervorum
Vasa vasorum
11
Q

Where does an artery usually run?

A

Down the midline, in the flexor compartment

12
Q

Arteries conduct high pressure blood. What confers this function?

A

The elastic fibres in the artery wall allow it to expand, and then bounce back to push the blood on

13
Q

How does the body control blood flow to different regions in different conditions?

A

The smooth muscle in the wall confers this property

When activated, the artery restricts in areas where excess blood is not needed.

The artery dilates where more blood is needed

14
Q

What is one of the main functions of arterioles?

A

‘Resistance vessels’

Control the flow and pressure into the capillaries

15
Q

What is the main function of capillaries?

A

‘Exchange vessels’

They have a very thin wall that allow them to carry out this function

16
Q

What is an anastomosis?

A

This is when two arteries meet without a communicating capillary

They provide collateral circulation

17
Q

What is collateral circulation?

A

Alternative routes of circulation

18
Q

We’re are anastomoses usually found?

A

In skeletal muscle

Joints, where circulation may be impaired due to bending of joint

19
Q

What is an anatomical end artery?

Where are they usually found?

A

These are arteries that do not connect with another artery

They are normally found in region that hang or stick out

Finger
Toes
Brain
Heart
Appendix
20
Q

What are the two types of end arteries?

A
  • Anatomical

* Functional / potential anastamosis

21
Q

Why are end arteries clinically important?

A

Blockage of an end artery by an embolus will cut of all blood supply to that region
Ischemia – necrosis

22
Q

Describe the vasculature of the end of a growing bone

A

The epiphyseal plate is avascular. Thus, there are two end arteries in the bone on either side.

When growth is finished, these arteries anastomose

23
Q

What is an end organ?

A

It is an organ whose blood supply is an end artery

24
Q

What are functional end arteries?

A

This is when, over time, end arteries anastomose due to some sort of pathology

Eg. In heart, an ongoing condition whereby the arteries are narrowed will cause anastomosis of coronary end arteries

In a sudden narrowing of vessels, there isn’t time for the arteries to anastomose, and tissue ischemia and necrosis will result

25
Q

What is the difference between a thrombus and an embolus?

A

Thrombus: fibrinous clot that forms and blocks a vessel

Embolus: obstruction present in circulation, may be a detached thrombus, or a gas bubble

26
Q

What is the structure of veins?

A

Intima: endothelium
Media: thin smooth muscle
Adventitia: fibrous material

27
Q

Why is the lumen in veins wider than in arteries?

A

Greater volume of blood which is at lower pressure

28
Q

Describe the function of valves

A

Valves are flaps of tissue in veins that close to prevent the back flow of blood

29
Q

What systems allow blood to be returned to the heart by the veins?

A
  • Venous valves
  • Muscular pump
  • Thoracic pump
30
Q

What defects can occur in venous valves?

A

Incompetent valves –> varicosed veins

31
Q

What is one of the special relationships between arteries and veins?

A

Venae comitantes

32
Q

Where are venous valves present?

A

In the veins of the appendages, not in the trunk
Especially in superficial veins

Valves in perforating veins moving through the deep fascia

33
Q

What are venae comitantes?

A

These are veins in close contact with arteries.

Function:
• Heat transfer
• Pulsation of arteries moves blood back to heart

34
Q

Describe how the muscular pump works

A

When skeletal muscle in the leg contracts, the veins embedded in the muscle are affected, and the blood in them is shunted up the veins

35
Q

Describe how the thoracic pump works to return blood

A

During inhalation, the pressure in the thoracic cavity drops slightly.
The blood flows into this region of lower pressure

36
Q

What does Boyle’s law say?

How does this apply to inhalation

A

When volume increases, pressure decreases

When one inhales, the volume in the thoracic cavity increases and the pressure decreases slightly

37
Q

What are perforating veins?

A

These are veins that perforate the deep fascia, and thus move blood from superficial veins into deep veins

38
Q

What is the deep fascia?

A

This is thick connective tissue surrounding skeletal muscle

39
Q

The presence of tortuous lumps in the veins indicates…

A

Varicosed veins

40
Q

What is the most important principle of lymph flow?

A

Lymph must pass through AT LEAST ONE lymph node before returning to circulation

41
Q

What is lymph made up of?

A

The tissue fluid that it drains:

  • plasma proteins
  • white blood cells
42
Q

Where is lymph returned to circulation?

A

In the veins in the neck

Right and left side

Left side receives lymph from most of the body

43
Q

What are the functions of lymph?

A
  • recovering proteins from interstitial fluid

- presenting invading organisms to the adaptive immune system

44
Q

What is one commonality between veins and lymph vessels?

A

Valves to ensure uni-directional flow

45
Q

What sort of tissue is a lymph node made up of?

A

Lymphatic tissue

46
Q

Where are lymph nodes predominantly found?

A

Cervical: neck
Axillary: armpits
Inguinal: groin

47
Q

Where is lymphatic tissue found?

A
Lymph nodes
Thymus
Tonsils
Peyer's patches: intestine
Spleen
48
Q

What causes elephantiasis?

A

A thread worm blocks the lymphatics.
Tissue fluid in the lower limbs is not drained
Oedema in the lower legs

50
Q

What is lymphedema?

A

This is when lymph nodes are resected in a surgery (ed. mastectomy) and the tissue fluid in the lower limbs does not drain

51
Q

What would a thromboembolus from the venous system potentially cause?

A

Pulmonary embolysm

52
Q

What would a thromboembolus from the arterial system potentially cause?

A

Stroke (in brain)

Decks in BIOM20002 - HSF Class (60):