Chapter 19 blood vessels
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Chapter 19 blood vessels
Simple s. epithelium and its the only layer present in capillaries and sub endothelium CT
Primarily smooth muscle and elastic CT and is important for maintaining blood pressure**active in vasoconstriction
Mainly collagen fibers, protect vessels and provide anchorage surrounding structures.** in larger vessels it has the vasa vasorum.
carry blood away from heart. O2 rich blood .
**only pulmonary artery carries bad blood
largest and most elastic
**it expands and relaxes as the heart pumps
**elastin makes it possible to handle high pressures
smallest arteries.they regulate blood flow to capillary beds.
Are the primary exchange vessel with tissuescarries blood from arterioles to venules.more capillaries go to bigger tissues like liver and heart.
Continuous capillaries (beds)
found in skin and muscles. joined by intercellular clefts. they allow limited passage of fluids and small solutes.
have intercellular clefts through the plasma membrane. found in kidneys, intestines and endocrine glands
**Needed for active absorption formation.
Found in bone marrow,spleen, adrenal medulla and liver.they permit entry & exit of large molecules **blood flows sluggishly
carry blood from capillary beds to the heart. they get larger along the way and their walls get thicker
are the smallest veins and they come together to make more of the veins.
Name some facts about the veins.
-little smooth muscle
-carry major portion of the blood(65%)
-they have thinner walls and have larger lumens than arteries.
twisted and dialted veins because of leaky valves.
can be hereditary. and happen because of leaky valves.can also due to increase venous pressure from straining. which leads to hemorroids.
specialized flattened veins, very thin walls (only endothelium)coronary sinus & dural sinus collect blood from veins.
Disease of plaque blocking the arteries and starts with a 1-fatty streak, then forms 2-fibrous plaque. then the plaque becomes unstable and prone to rupture and becomes 3-complicated plaque.
1-volume of blood flowing through a vessel or organ.
2- the force of against vessel walls
3-opposition to blood flow caused by friction of blood against wall.
arteriol blood pressure reflects 2 factors what are they
how much the elastic arteries can stretch and the volume of blood forced into them
what is mean arterial pressure (MAP)
pressure that sends blood to tissues. Map is equal to diastolic pressure plus one third of the pulse pressure.**P.pressure + MAP = BP
Facts about capillary blood pressure
35-17 mmHG fragile walls cant take high pressures. and most of them don't need much force to get it out of interstitial fluid.
changes pressures in thoracic and abdominal cavities and moves the blood twords the heart.
short term regulation of blood pressure
done by nervous system and hormones.1- maintains BP by altering vessel diameter2-alter blood distribution to respond to needs of organs.
whats in the cardiovascular center
cardio-acceleratory, cardioihibitory and vasomotor centers
**modified by baroreceptors, chemo receptors and higher brain centers.
what are baroreceptors
Stretch receptors in the carotid sinuses, aortic arch and large arteries of the thorax.
**when stretched they send a signal to the cardiovascular center and it lowers its blood pressure as a result.
Baroreceptor refelexes vasodilation
arteriolar vasodialation- arterioles dialate an dperiphreal resistance falls.
venodialation- veins dilate and shifts blood to reservoirs and decreases venous output and cardiac output.
Decreased CO-inhibition of sympathetic activity leads to reduced HR lowering CO and MAP.
Carotid sinus reflex
protect the blood supply to the brain
** short term changes. but cant protect us from sustained pressure changes
sensory neurons in carotid & aortic arteries
activated by a rise CO2
stimulates vasomotor centers to constrict arterioles and cardio acceleratory to increase CO and raise BP
what is hypertention
systolic above 140 and diastolic over 90 "silent killer"
**it strains the heart and damages blood vessels.
what is primary hypertension?
90% of people and caused by heredity, diet, obesity, age, stress and smoking
what is secondary hypertention
due to kidney disease,
-obstructed renal arteries,
what is hypotension
-only a problem if it leads to inadequate blood flow
**elderly gets orthostatic hypotention- temporary drop in bp due to temporary aging sympathetic NS.
describe tissue perfusion
1-deliver oxygen and nutrients and remove waste.
2-exchange O2 in lungs
3- absorb nutrients in digestive tract.
4-form urine in the kidney
**blood flow is constant and controlled to organs.
describe the velocity of blood flow.
1-fastest in aorta
2-slowest capillaries for exchange
3- faster in veins and organs choose how much blood they wanna get.
how do tissues auto regulate their blood flow?
- low oxygen and high potassium,hydrogen, prostaglandins vasodialate and the endothelial cells release nitrc oxide
-endothelium also release endothelins to vaso constric.
describe the blood flow to the ...
-constant rate, neurons sensitive to decilining PH, and high CO2
-low oxygen- local vasoconstriction
high oxygen- local vaso dilation
heart-blood remains constant except.
whats is blood bulk flow
hydrostatic pressures- the force of blood flow against the wall varies from arterial to venous blood flow it pushes shit.
colloid osmatic pressure created by non diffusable molecules and it pulls shit.
what is circulatory shock
blood vessels are not properly filled and cannot circulate normally to feed tissues and organs will die.
what is the hypovolmic shock?
what is cardiogenic shock?
-large scale fluid loss (increased HR and vaso constriction)
-heart is inefficient cannot circulate properly and usually causes heart attack.
describe the different vascular shocks.
anaphylactic- system allergic reaction
neurogenic shock- failure of ANS regulation
septic shock- severe systemic bacterial infections (vasodialators)
how does it come in...
and how does it go
1-bring blood to alveoli
3- RV to pulmonary trunk, then makes two arteries
Exchange occurs in the capillaries..it then drains into 2 pulmonary veins from each lung.
1- delivers nutrients and oxygen to tissue cells and also removes CO2 and waste.
2-LV out the aorta to all the capilliary beds. after its all done it goes to the veins and back into the vena cava and into the right atrium.
describe the hepatic portal system
1-name the 2 beds
2-what are the major vessels
3-what is the function
1st bed is made of several organs and the 2nd is the liver.
the major vessels are the superior and inferior mesentaric vein and the splenic vein.
carries the nutrient rich blood to the liver and the excess is stored. And phagocytic cells rid blood of bacteria.
Decribe the fetal circulation
umbilical arteries- fetus TO placenta
umbilcal veins- Placenta TO fetus
ductous venosus- by passes the fetal liver
foramen ovale and ductus arteriosus- bypass the fetal lungs.