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Arteries and veins are composed of which 3 tunics?
- tunica internal (intima)
- tunica media
- tunica externa (adverntitia)
What are capillaries composed of?
endothelium w/ sparse basal lamina
How does blood travel through the aorta?
blood goes up the ascending aorta to the arch into the brachiocephalic, carotid, and subclavian arteries, down the descending aorta into the thoracic aorta passed the diaphragm and into the abdominal aorta where it is spread into the lower parts of the body
What 3 arteries are in the arch, where do they go, and which 1 is separated into parts?
- Brachiocephalic > right side of the body
- -right carotid > right side of the head
- -right subclavian > right side of upper body
- Carotid > left side of head
- Subclavian > left side of upper body
What is tunica interna (intima)?
endothelial layers that lines the lumen of all vessels
What is tunica media?
smooth muscle and elastic fiber layer, regulated by sympathetic nervous system
What is tunica externa (adventitia)?
collagen fibers that protect and reinforce vessels
List the Arterial system groups
- elastic (conducting) arteries
- muscular (distributing) arteries
What are elastic (conducting) arteries?
- Thick-walled arteries near the heart, the aorta, and its major branches
- - contains elasrin in all 3 tunics
- - withstand and smooth out large blood pressure fluctuations
What is muscular (distributing) arteries?
- distal to elastic arteries; deliver blood to body organs
- -have thick tunica media w/ more smooth muscle
- -active in vasocontriction
What are arterioles?
- smallest arteries; lead to capillary beds
- -control flow into capillary beds via vasodialation and constriction
What are capillaries?
- Smallest blood vessels
- -walls consisting of thin tunica interna, 1 cell thick
- -allow only a single RBC to pass at a time
- -Pericytes on the outer surface stabilize their walls
- There are 3 structural types:
What are continuous arteries?
- abundant in the skin and muscles
- each cell is attached to each others by a tight junction
- can be broken after continuous tapping
What are Fenestrated capillaries?
found wherever active capillary absorption or filitration formation occurs (eg; small intestines, endocrine glands, & kidneys)
What are sinusoids?
found in liver, bone marrow, lymphoid tissue, & in some endocrine organs
What are capillary beds?
- a microcirculation of interwoven networks of capillaries, consisting of: vascular shunts and true capillaries
- sphincter: gates that can close the vessels
What is blood pressure?
- force per unit area exerted on the wall of a blood vessel by its contained blood
- expressed in millimeters of mercury (mm Hg)
- measured in reference to systemic arterial BP in large arteries near the heart
What is the opposition of flow?
resistance aka peripheral resistance (PR)
What are the 3 most important sources of resistance?
- blood viscosity
- total blood vessel length
- blood vessel diameter
Venous Blood Pressure is __1___ and = ___2___
What are the main factors that inflence BP?
- cardiac output (CO)
- peripheral resistance (PR)
- Blood Volume (BV)
What is the formula for BP?
How can BP be controlled?
- short term: mediated by nervous system and blood borne chemicals
- long term: regulate blood vloume
What chemoreceptor reflexes that are sensitive to O2 and CO2 that help regulate BP for a short term?
- adernal medulla hormones
- antidivertic hormones (ADH)
- angiotensin II
- nitric oxide (NO)
- endothelium derived factors
- inflammatory chemicals
- alcohol (drops by inhibiting ADH)
What is the most potentate dilator in the body?
Nitric Oxide (NO)
How does the long term mechanism of renal regulation work?
- increased BP stimulated kindneys to eliminate water, thus reducing BP
- decreased BP stimulates the kidneys to increase BV and BP
How do renin-angiotensin-aldosterone regulate BP?
- juxtaglomerular cell senses drop in bp, releases renin in response to decrease in bp, renin releases in circulation (leaves the kidney)
- renin circulates to liver, converts angiotensinogen to angiotensin I
- angiotensin I circulates to lung, angiotensin I converts to angiotensin II
- angiotensin II circulates to adrenal gland, angiotensin II stimulates and releases aldosterone
- aldosterone circulates to kidney, retains Na+ and Cl-
- angiotensin II circulates to kidney
- angiotensin II vasoconstricts afferent ateriole, less filterate, less Na+ , lost nephron
how do you measure circulatory efficiency?
vital signs- pulse and bp, along with respiratory rate and body temp.
what is a pulse?
pressure wave caused by the expansion and recoil of elastic arteries
what is hypotension?
low bp in which systolic pressure is blow 100 mm Hg
what is hypertension?
- condition of sustained elevated arterial pressure of 140/90 or higher
- maybe transient or persistent
- primary hypertension- obesity, age, race, heredity, stress, and smoking
- secondary hypertension- identifiable disorders: excessive renin secreation, arteriosclerosis, endocrine disorders
what is autoregulation?
automatic adjustment of blood flow to each tissue in proportion to its requirements at ay given time
when in long term autoregulation does angiogenesis takes place?
- as the # of vessels to a region increase
- when existing vessels enlarge
- when a heart vessel becomes partly occluded
- routinely in people in high altitudes, where O2 content of air is low
what are the 3 types of circulatory shock?
- hypovolemic shock: results from large scale blood loss
- vascular shock: poor circulation resulting from extreme vasodialation
- cadiogenic shock: heart cannot sustain adequate circulation
what are the 3Ps?
- pump-right and left side
- pipes- blood vessels
types of shock related to 3Ps:
- pump > cardiogenic shock > no pump
- plasma > hypovolemic shock > no fluid (internal/external hemorage)
- pipes > septic and neurogenic (vascular shock) > too dialted so body thinks not enough fluid
how does fetal circulation work?
- O2 from placenta reaches heart via fetal veins in umbilical cord -bypasses liver
- heart pumps oxygenated blood to capillaries in all fetal tissues including lungs
- umbilical artery branch of iliac artery to return blood to the placenta
what are the 2 circulatory pathways in the vascular system?
- pulmonary circulation- short loop that runs from the heart to the lungs and back to the heart
- systemic circulation- routes blood through a long loop to all parts of teh body and returns to the heart.