Lecture 14 Vessels and Circulation

Question 1

Classes of Vessels

Answer 1

1. Arteries: take blood away from heart
2. Capillaries: tiny blood vessels where gas exchange occurs and distribution of nutrients
3. Veins: return blood back to heart

Question 2

Pathway of Vessels

Answer 2

arteries move blood from heart to capillaries move blood to veins, veins return blood back to heart

Question 3

Anastomoses

Answer 3

Anastomoses : converging arteries and/or veins for the purpose of having alternative routes

Question 4

End Arteries

Answer 4

End arteries: one pathway for blood to travel

Question 5

Functional end arteries

Answer 5

Functional end arteries : are small anastomoses but act like end arteries still use only one path over again

Question 6

Companion Vessels

Answer 6

Companion Vessels: corresponding vessel for an artery , an artery has a companion vessel of a vein .

Question 7

What are Tunics

Answer 7

Layers of arteries and veins

Question 8

what are the three tunics

Answer 8

Tunica Externa: simple squamous and areolar CT
Tunica Media: smooth muscles middle meaty part
Tunica Intima: simple squamous and areolar CT, internal layer

Question 9

what is the function of arteries

Answer 9

Transport blood away from the heart

Question 10

what are the characteristics of arteries

Answer 10

Thick tunica media
Contains more collagen for strength and elastic for stretching and recoil
High pressure because the blood is leaving the heart
small lumen

Question 11

What are the three types of arteries

Answer 11

1. Elastic arteries: biggest and most flexible
2. Muscular arteries: are going to be majority /most common
3. Arterioles: small arteries

Question 12

Elastic Arteries

Answer 12

Size: largest
the artieres near heart
- Increased elastic fibers, Will have elastic because they are the largest and very close to the heart
Increase of elastic fibers make it possible for artery to keep up with the high pressure and strength for pumping blood

Question 13

Examples of elastic arteries

Answer 13

pulmonary artery, aorta, brachiocephalic, common carotid , subclavian

Question 14

Muscular arteries

Answer 14

• Medium size
• Distributing arteries because they distribute blood throughout the body (organs and tissues)
• Thicker tunica media, less elastic fibers, more muscle, muscle artery
• *Better vasoconstricting and vasodilation
• *Vasoconstriction: constricting lumen lessen blood to go through
• *Vasodilation: relax to allow blood to flow through

Question 15

What are examples of muscular arteries

Answer 15

brachial, anterior tibial, coronary

Question 16

Aterioles

Answer 16

Smallest
Control blood flow to capillaries
Important because they are the last part before capillaries , last part before capillaries
Capillaries do not have smooth muscle. So it can not control blood
Last point of blood control is arterioles
Vasodilate and Vasoconstriction to help regulate blood pressure

Question 17

Function of Capillaries

Answer 17

• Function:
• Rapid gas and nutrient exchange
• “Functional units”
  Functional units: capillaries work together in capillary bed, capillary gives nourishment to tissues
  Only place where gas is exchanged

Question 18

Characteristics of Capillaries

Answer 18

Considered the smallest vessel, size of one rbc fits into a capillary
Only a tunica intima
Clefts: spaces in between the capillary which allow certain things to travel through
No smooth muscle only endothelium (thin layer)
Capillary bed is fed by metarteriole
Distal end is called thoroughfare channel and it has no smooth muscle
Thoroughfare channel lead to venual known as postcapillary venule
Proximal: smooth muscle

Question 19

What are the types of capillaries

Answer 19

1. Continuous capillaries
2. Fenestrated capillaries
3. Sinusoids

Question 20

Continuous Capillaries

Answer 20

• Most common
• Tight junctions
  Tight junctions : connect cells together adhesions

Question 21

Location of Continuous Capillaries

Answer 21

• Locations: muscles, skin, lungs, thymus, CNS

Question 22

Fenestrated Capillaires

Answer 22

Small holes
- Allow fluid exchange
Small holes looked punctured
Holes allow for fluid exchange
Small holes looked punctured
Holes allow for fluid exchange
Think kidneys filters fluid

Question 23

Locations of Fenestrated Capillaries

Answer 23

Location: Kidneys and intestines

Think kidneys filters fluid

Question 24

Sinusoids

Answer 24

Large gaps/openings
- Allows exchange of larger materials and cells
Think process of recycling blood for this type of capillary

Question 25

Location of Sinusoids

Answer 25

Location: spleen, liver

Question 26

Function of Veins

Answer 26

Function: - Transport blood to the heart (Brings blood back to the heart - Blood reservoirs

Question 27

Characteristics of Veins

Answer 27

Lumen of veins is very big/large Blood reservoirs, they can hold a lot of blood Veins contain valves to help prevent back flow Thicker Tunica Externa (outer layer ) Low pressure

Question 28

what are the two types of veins

Answer 28

1. Venules | 2. Veins

Question 29

Venules

Answer 29

Size: small | - CompSize large anion: arterioles

Question 30

What are the featres of venules

Answer 30

Postcapillary venules: what drains the capillaries, | Diapedesis: ability for WBC to migrate into the interstitial fluid,

Question 31

Veins

Answer 31

Size large | Companion vessels: muscular and elastic arteries

Question 32

Features of veins

Answer 32

Skeletal muscle pump: very efficient, both sides of the vein will have skeletal muscle, the skeletal muscle can contract, once it contracts they squeeze on vein pushing blood either upward toward heart or keeps it from going back , when relaxed it sucks blood up Valves: promotes blood flowing upward , but can not go back

Question 33

Structures of Newborn Circulation

Answer 33

- Ductus arteriosus - Ductus venosus - Foramen ovale

Question 34

Ductus Arteriosus

Answer 34

Ductus arteriosus is a vessel between pulmonary trunk and aorta, your not using your lungs, no need for pulmonary circulation because you get O2 blood from mother, so it is bypassed Adult: ligamentum arteriosum, the ductus arteiosus collapses and turns into the ligamentum arteriosum

Question 35

Ductus Venosus

Answer 35

Vessel meant to bypass liver, Fetus has no functional GI tract Adult: ligamentum venosum

Question 36

Foramen Ovale

Answer 36

Oval shaped hole between right atrium and left atrium why: to bypass pulmonary circulation Adult: foramen ovale flap falls over hole and becomes an indentation on right atrium wall known as fossa ovalis

Question 37

Circulation pathway

Answer 37

Blood comes from Systemic Circulation (SVC, CS, IVC),then enters the right atrum, goes through the tricuspid valve,enters the right ventricle, right ventricle pumps it through the pulmonary semilunar valve into the pulmonary trunk and arteries, goes to lungs and comes back to heart oxygenated through [aired pulmonary veins,. Then enters the left atrium and goes through the bscuspid valve, next entering the left ventricle which will eject blood through the aortic semilunar valve, goes up ascending aorta into the aortic arch and t the descending thoracic aortaback to the systemic circualtion.