Lecture 9: Heart and Blood Vessels

Question 1

Functions of the Cardiovascular system

Answer 1

• movement of body fluids
• transport of oxygen and nutrients to the tissues
• transport of carbon dioxide and waste products from the tissues
• temperature regulation
• distribution of hormones
• mediation of immune response- transport of immune cells

Question 2

Flow of blood through the heart:

Answer 2

inferior/superior vena cava
right atrium
tricuspid valve
right ventricle
pulmonary semi lunar valve
pulmonary arteries 
lungs
pulmonary veins
left atrium
bicuspid valve
left ventricle
aortic semilunar valve
aorta 
arteries

Question 3

Layers of the heart wall include?

Answer 3

Epicardium
-mesothelium
-CT (BV, nerves)
Myocardium
-cardiac muscles
Endocardium
-endothelium
-CT- conducting system

Question 4

Heart components: fibrous skeleton

Answer 4

components
-4 fibrous rings surrounding the valve openings
-2 trigones (connect the rings)
attachment of
-cardiac muscle
-valves (cuspid and semilunar)

Question 5

Conducting system of the heart

Answer 5

sinoatrial- generate/conduct APs through heart
atroventricular node
-transmission of APS from SA node
Purkinje cells/fibres and bundle branches
-modified cardiac muscle cells
-generate and conduct APs

Question 6

Purkinje fibres

Answer 6

location
-within CT of the endocardium
-appear to be between endocardium and mycardium
characteristics
-large cells
-peripheral myofibrils
-pale/pink cytoplasm
-almost appear foamy
-found in groups

Question 7

Cardiac Muscles

Answer 7

• composes the myocardium

- principal component of the heart

Question 8

Vessels

Answer 8

tunica intima
-innermost layer
-single layer of endothelium
-supported by basement membrane
-loose CT
tunica media
-middle layer
-primarily smooth muscle cells 
tunica adventitia 
-outermost layer
-CT collagen and elastic fibre

Question 9

Where are elastic arteries located?

Answer 9

major distribution vessels- aorta, pulmonary artery

Question 10

Characteristics of pulmonary arteries include?

Answer 10

inconspicuous internal elastic membrane (lamina)

• substantial tunica media- SM + elastic lamella
• vasa vasorum

Question 11

Where are muscle arteries located

Answer 11

distributing branches- radial, femoral, coronary

Question 12

Characteristics of muscle arteries

Answer 12

• prominent internal elastic lamina (IEL) and external elastic lamina (EEL)
• more SM and less elastin in the tunica media than elastic arteries
• vasa vaorum may be visible in large muscular arteries

Question 13

Small arteries and arterioles supply/

Answer 13

capillary beds- located everywhere

Question 14

Small artery/arteriole characteristics

Answer 14

tunica media-
-small arteries up to 8 layers SM
-arterioles have 1-2 layers
Tunica adventitia is thin and merges with surroundin CT

Question 15

Types of capillaries

Answer 15

Continuous, Fenestrated, Discontinuous

Question 16

Continuous capillaries

Answer 16

• muscle, lung, CNS
• occluding junctions
  - only allow passage of small molecules
• pericytes may be ass with endothelium

Question 17

Fenestrated capillaries

Answer 17

endocrine glands, kidney, intestine
Characteristics
-fenestrations provide channels across capillary wall
-pericytes rarely associated with this capillary type

Question 18

Discontinuous (Sinusoid)

Answer 18

liver, spleen, bone marrow 
Characteristics
-fenestra and pores
-pores lack a BM beneath the endothelium
-larger capillary diameter
-highly permeable

Question 19

Venules and Small Veins

Answer 19

location: any small vessels that collect blood from capillaries or is a terminal branch of a vein
Characteristics
-small veins are less than 1mm in diameter and continuous with venules
-tunica media may consist of 1-few layers of SM

Question 20

Medium vein

Answer 20

location: radial vein, tibial vein 
Characteristics
tunica intima
-usually diameter is less that 10 mm
-endothelium +BM, may see thin IEL
Tunica media
-thin compared to same-sized artery
-consist of 2-4 layers of SM, some collagen and elastic fibres 
Tunica adventita 
-thickest layer
-collagen and networks of elastic fibres 
-may see vasa vasorum

Question 21

Large vein

Answer 21

location: superior and inferior vena cava 
characteristics:
usually diameter is greater than 10mm 
tunica intima
-endothelial lining + BM
-boundary with tunica media is unclear 
tunica media
-relatively thin
-more than 4 layers ofSM
Tunica adventita
-broad
-SM and collagen bundles may be seen 
-contains vasa vasorum