Test 2 Anatomy and Physiology

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Human Anatomy & Physiology
Chapters 19, 20
Blood Vessels and Lymphatic
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1

Major Types of Blood Vessels

Aorta, Arteries, Arterioles, Capillaries, Venules, Veins, Superior Vena Cava, Inferior Vena Cava

2

Arteries

Carry blood away from the heart

Branch

Carry oxygenated except for pulmonary circulation and umbilical vessels of fetus.

3

Capillaries

Direct contact with tissue cells

Directly serve cellular needs

known as exchange vessels

Composed of simple squamous epithelium

4

Veins

Carry blood towards the heart

veins merge

Carry deoxygenated except for pulmonary circulation and umbilical vessels of fetus.

5

Lymphatic System

Recovers excess tissue fluid that leaks from circulation and returns fluid (lymph) to blood.

6

Three layers of Blood Vessels

Tunica intima: Innermost layer that is in " intimate" contact with blood

Tunica Media: Middle layer composed of smooth muscle of elastic CT

Tunica Externa: Outermost layer

7

Tunica Intima

Simple Squamous ET

flat and slick surface to reduces friction

8

Tunica Media

(Thickest in Arteries)

Sympathetic vasomotor nerve fibers innervate smooth muscle

controls vasoconstriction or vasodilation

Increase Sympathetic stimulation Increase constriction (vasoconstriction)

Decrease sympathetic stimulation decrease constriction (vasodilation)

9

Vasoconstriction

lumen diameter decrease as smooth muscle contracts; less blood delivered decrease blood flow

10

Vasodilation

Lumen diameter increase as smooth muscle relaxes; more blood delivered increase blood flow.

11

blood pressure

Circulation (where blood goes)

Tunica Media

12

Tunica Externa

Also called Tunica adventitia

composed mostly of loose collagen fibers that protect and reinforce BV wall

13

Vasa Vasorum

BVs to nourish BV wall; system of tiny blood vessels to nourish outermost external layer of BV wall; whereas, the lumen of BV obtain nutrients directly from blood in lumen.

14

Elastic Arteries

located near heart, conduct blood away from heart and called conducting arteries

Act as pressure reservoirs by expanding during systole and recoiling during diastole

15

Why aterioclerosis is so dangerous?

Because affected blood vessels do not smooth out BP

16

Arterioles smooth muscle contracts

Lumen diameter is constricted (increase resistance) and capillary bed served is bypassed

17

Arterioles smooth muscle relaxes

Lumen diameter dilates blood vessel (decrease resistance ) and the capillary bed is perfused with increased blood flow.

18

Capillaries are called exchange vessels

Because gases, nutrients, wastes and hormones are exchanged between blood and interstitial fluid.

19

Example of highly vascularized tissue

Nasal Mucosa

Spleen

Kidneys

Tumors

20

Examples of poorly vascularized tissue

Tendons

Ligaments

(slow to heel)

21

Examples of Avascular (no blood vessels) tissue

Cartilage, Epithelial Tissue, cornea, lens of eye

22

Intercellular clefts

Allows passage of fluids and small solutes. Leakier capillaries have specialized passageways that increase fluid movement.

23

Three types of Capillaries

  • Continuous
  • Fenestrated
  • sinusoid
24

Continuous Capillary

in the brain form the blood brain barrier because they lack intercellular clefts and are totally enclosed with continuous tight junctions

25

Fenestrated Capillary

Have large pores that increase permeability

Found in areas involved involved in filtration as in the kidneys, absorption as in intestines, and in endocrine tissue for hormone secretion think "swiss cheese like holes"

26

Sinusoidal Capillary

Most Permeable and occur in limited locations

Found only in the liver, bone marrow, spleen, and adrenal medulla

27

Capillary Beds

blood flows through

28

Two types of vessels make up microcirculation in capillary beds

  • Vascular shunt
  • true capillaries
29

Microcirculation

blood flow from arteriole to venule through the capillary bed

30

Vascular Shunt

Metarteriole and the thoroughfare channel that connect arteriole with venule and blood bypasses the capillary bed

31

true capillary

branch into 10 to 100 exchange vessels (capillary bed) and normally branch from metarteriole

32

Precapillary Sphincters open

blood flows into the true capillary

33

Precapillary Sphincters close

blood flows through metarteriole

34

During vigorous excerise

  • Precapillary sphincters are open going to skeletal muscle
  • Precapillary sphincters are closed going into the digestive system
35

Veins have a large diameter lumen that offer little resistance ; increase lumen diameter decrease resistance

...

36

What are examples of Venous Sinuses?

Coronary sinus of the heart

Dural sinuses of the brain

37

What are Varicose veins?

Dilated and painful veins due to incompetent (leaky) valves

Normally located in lower limbs

38

Review:

  1. Heart=Pump
  2. Arteries=pressure reservoirs, conduits
  3. Arterioles=resistance vessels, control distribution
  4. Capillaries=exchange sites
  5. veins= blood reservoirs, conduits

...

39

What is blood flow?

volume of blood flowing through a vessel or an organ

varies based on need

40

what is blood pressure?

force of blood exerted on wall of blood vessel expressed in mm hg

41

BP systolic/diastolic

Normal Adult: 120/80

Newborn Baby: 90/55

Hypertension: 140/90

42

Three factors of resistance

  • blood viscosity (thickness or stickiness)
  • total blood vessel length
  • blood vessel diameter
43

Viscosity effects resistance

increases blood viscosity increase resistance

increase BV increase resistance decrease blood flow

44

Polythemia

increase BV increase resistance decrease blood flow

45

Anemia

decrease viscosity decrease resistance increase blood flow

46

Vessel length effect resistance

increase BV length increase resistance decrease blood flow

47

Vessel Diameter effects resistance

Greatest influence on resistance

Dilate BV: decrease resistance

Constrict BV: increase resistance

48

Inversely

Means opposite

ex. Increase lumen decrease resistance

49

Mean Arterial Pressure= MAP

BP that propels blood through circulation and to tissues

50

Pulse Points

Superficial Temporal

Facial

Common Carotid

Brachial

Femoral

Popliteal

Posterior Tibial

Dorsalis pedis

51

Factors aiding in venous return to heart

  1. muscular pump
  2. respiratory pump
  3. Sympathetic venoconstriction
52

three main variable in regulating BP

  1. Cardiac output
  2. Peripheral Resistance
  3. Blood volume
53

Vasomotor

increase sympathetic activity increase vasoconstriction increase BP

decrease symphathetic activity decrease vasoconstriction decrease BP

54

What happens when arterioles vasodilate?

decrease peripheral resistance decrease BP

55

What happens when veins vasodilate?

decrease venous return decrease CO decrease BP

56

Pathway

Angiotensinogen+renin > Angiotensin1

Angiotensin1+ACE>Angiotensin 2

57

Intrinsic controls

local autoregulation to distribute blood to individual organs and tissue as needed.

58

Extrinsic controls

involves sympathetic nervous system/ hormones to control blood flow through whole body to maintain BP and blood flow

59

Lymphatic System

Returns excess tissue fluid and proteins that have leaked from blood vessels back to blood.

60

Three major parts of the lymphatic system

  1. Network of lymphatic vessels
  2. lymph: fluid in lymphatic vessels
  3. lymph nodes: cleanse lymph
61

What are the structures of lymphatic system?

  1. spleen
  2. thymus
  3. tonsils
  4. lymph nodes
  5. other lymphoid tissues
62

Lymphatic capillaries are absent from

  • bones
  • teeth
  • bone marrow
  • CNS
63

How does leaked proteins in interstitial fluid get back into the blood?

proteins moved into permeable lymphatic capillaries because of higher IF pressure

64

what are lacteals?

specialized lymph capillaries present in small intestine mucosa

they digest fat and deliver fatty lymph to the left subclavian vein

65

pathway of lymph

  1. lymphatic capillaries
  2. lymphatic vessels
  3. lymphatic trunks
  4. lymphatic dunks
66

lymphoid cells consist of

  1. T cells
  2. B cells
  3. Macrophages
  4. Dendritic cells
67

Lymphocytes mature into two main types

T cells

B cells

68

T cells

thymus derived

69

B cells

Bone derived

70

Antigens

anything the body perceives as foreign and stimulates an immune response

71

Examples of Pathogenic antigens

  1. bacteria
  2. toxins
  3. viruses
  4. fungi
  5. protozoa
  6. mismatched RBCs
  7. Cancer cells
72

how does t cell protect?

helper t cells : help in cloning

regulatory t cells: dampen immune response

cytotoxin t cell: attack and destroy infected cell

73

how does b cells protect?

plasma cells: secrete antibodies

antibodies bind to antigens in ECF

mark them for destruction by phagocytosis or other means