LP #105 The Circulatory System Flashcards
1
Q
- complex network of vessels
- basic fxn: deliver oxygen & nutrients to the cells, & remove tissue wastes
- primary role n maintaining homeostasis
A
Circulatory system
2
Q
2 components to circulatory system
A
- cardiovascular-2-way system:
- delivers blood to tissues
- removes it from tissues returns it to heart
- lymphatic- one-way:
- removes excess fluid from tissues & returns it general circulation
3
Q
Vascular system is a network consisting of 3 types of blood vessels:
A
- arteries: carry blood away from heart
- Blood capillaries: site of exchange of o2/ nutrients & sates
* extensive network - Veins: return blood to heart
4
Q
Carry fluid that leaks out of blood vessels into interstitial spaces & transports it back to heart=
A
Lymphatic vessels
5
Q
3 lymphatic vessels=
A
- lymph capillaries
- lymphatic collecting vessels
- lymphatic trunks
6
Q
Tunica: layer
- inner layer?
- middle layer?
- outer layer?
A
- Tunica intima
- Tunica media
- Tunica adventitia
7
Q
- aka tunica interna
- inner most layer
- composition: simple squamous cells; form a smooth endothelial surface- reduces friction to blood flow
- in direct contact with blood
A
Tunica intima
8
Q
- middle & largest layer
- composition: mostly smooth muscle fibers arranged in circular layers
- responds to sympathetic Innervation
- changes to diameter of bv lumen (vasodilation/ vasoconstriction)
A
Tunica media
9
Q
- aka tunica adventitia
- outermost layer, relatively thin
- composition: loosely arranged collagen fibres
- protect & anchor vessel to surrounding structures
- forms mesh network containing nerve fibres, small blood vessels & lymphatic vessels that serve the artery itself
A
Tunica externa
10
Q
- carry blood away from heart
- diverge from large to small vessels
- systemic arterial blood is oxygenated
- arteries begin in heart and end, via arterioles, in capillary beds
- relative size of layers varies between types of aa
A
Arteries
11
Q
Types of arteries
A
- elastic (conducting)
- muscular (distributing)
- arterioles
12
Q
- large diameter blood vessels
- carry blood from heart
- contain mostly elastin in tunica media
A
Elastic (conducting)
13
Q
- smaller diameter blood vessels
- contain more smooth mm than elastin
A
Muscular (distributing)
14
Q
- smallest diameter blood vessels
- contain mostly smooth mm
A
Arterioles
15
Q
- carry blood towards heart
- converge from small to larger vessels
- systemic venous blood is deoxygenated
- veins begin in capillary beds (as venules) & end in heart
A
Veins
16
Q
Types of veins
A
- Venules
2. Veins
17
Q
- small vessels
- transport blood from tissues to larger veins
- endothelium covered by fibroblastic cells
- thin tunic intima & tunica externa
- porous
A
Venules
18
Q
- small, thin vessels in tissues
- tunica externa is thickest layer
- tunica media relatively thin
- large lumen
- contain valves
A
Veins
19
Q
Structures of veins determine fxns:
- large lumen:?
- little muscle:?
- valves:?
A
- Blood reservoir
- Need help returning blood to heart (mostly against gravity)
- (Extensions of Tuncia intima) prevent back flow of blood
20
Q
Mechanisms that assist venous return
A
- skeletal mm contractions
- breathing
- valves
21
Q
- smallest blood vessels
- walls are 1 cell thick: Tuncia intima only
- fxn: site of gas/fluid exchange betweeen arterial & venous sides of circulatory system
A
Capillaries
22
Q
Types of capillaries
A
- Continuous
- Fenestrated
- Sinusoidal
23
Q
- cells joined by tight junctions
- intercellular clefts: breaks b/w cells
- limited passage of fluids & volutes
- found in:
- skin
- mms
- brain
A
Continuous
24
Q
- large pores covered by network of proteins (basal lamina)
- allow larger organic molecules & greater volume o fluid to flow into interstitial space
- found where absorption/ secretion is required, ex.
- intestine
- endocrine glands
A
Fenestrated
25
- leaky: large intercellular clefts
- passage of proteins & blood cells into interstitial space
- found where passage of large particles is necessary, ex.
* liver
* bone marrow
* lymphoid tissue
26
-capillary bed=
Large capillary network
27
2 components of capillary bed
- vascular shunts
| - true capillaries
28
- short vessels b/w arterioles & venule
- main thoroughfare from one side of capillary bed to other
- also known as a metarteriole
Vascular shunt
29
- side-spread network of blood vessels
| - reach all tissue areas
True capillaries
30
- leads into metarteriole
- joints to postcapillary venule that drains capillary beds
- feeds capillary bed
Terminal arteriole
31
- found between metarterioles & capillaries
- smooth mm rings that constrict lumen to restrict blood flow to capillaries
- minimize BF to areas requiring less blood at a given time
Pre-capillary sphincters
32
- many tissues receive blood from more than one vessel
* anatomical & physiological redundancy
- margining of 2 or mor blood vessels to a region is called an anastomosis
- both arteries & veins anastomose
* veins more than arteries
Vascular anastomoses
33
- cyclical from heart to lungs & back to heart
- in pulmonary circuit:
* arteries carry deoxygenated blood away from heart (to lungs)
* veins carry freshly oxygenated blood to heart (from lungs)
Pulmonary system
34
- returns leaked fluid (lymph) to general circulation
- important in maintaining fluid balance
- 3-4L of lymph produced daily (2/3 blood vol)
- lymphatic system is one-way system (unlike cardiovascular system)
- as lymph travels toward venous system (ultimately into subclavian veins), it is cleansed by WBC-rich lymph nodes
Lymphatic system
35
lymphatic system:
| Adaptations?
- minivalves
| - anchors
36
Lymph flows into progressively larger vessels:
```
Lymph capillaries
To
Collecting vessels
To
Trunks
To
Ducts
```
37
Lymphatic system:
- larger vessels have same 3 tunics as veins, but much thinner
- lymphatic valves have many more valves than veins
- mechanisms hat assist lymph return: ?
- skeletal mm contractions
- breathing
- valves
- movement of surrounding tissue
*both components of the circulatory system are important o maintaining fluid balance in the body.
