Blood Vessels

• tunica internal (intima)
• tunica media
• tunica externa (adverntitia)

endothelium w/ sparse basal lamina

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

• 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

endothelial layers that lines the lumen of all vessels

smooth muscle and elastic fiber layer, regulated by sympathetic nervous system

collagen fibers that protect and reinforce vessels

• elastic (conducting) arteries
• muscular (distributing) arteries
• arterioles

• 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

• distal to elastic arteries; deliver blood to body organs
• -have thick tunica media w/ more smooth muscle
• -active in vasocontriction

• smallest arteries; lead to capillary beds
• -control flow into capillary beds via vasodialation and constriction

• 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:
• -Continuous
• -Fenestrated
• -Sinusoid

• abundant in the skin and muscles
• each cell is attached to each others by a tight junction
• can be broken after continuous tapping

found wherever active capillary absorption or filitration formation occurs (eg; small intestines, endocrine glands, & kidneys)

found in liver, bone marrow, lymphoid tissue, & in some endocrine organs

• a microcirculation of interwoven networks of capillaries, consisting of: vascular shunts and true capillaries
• sphincter: gates that can close the vessels

• 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

resistance aka peripheral resistance (PR)

• blood viscosity
• total blood vessel length
• blood vessel diameter

• 1. steady
• 2. 20 mm Hg

• cardiac output (CO)
• peripheral resistance (PR)
• Blood Volume (BV)

BP=COxPR

• short term: mediated by nervous system and blood borne chemicals
• long term: regulate blood vloume

• adernal medulla hormones
• antidivertic hormones (ADH)
• angiotensin II
• nitric oxide (NO)
• endothelium derived factors
• inflammatory chemicals
• alcohol (drops by inhibiting ADH)

Nitric Oxide (NO)

• increased BP stimulated kindneys to eliminate water, thus reducing BP
• decreased BP stimulates the kidneys to increase BV and 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

vital signs- pulse and bp, along with respiratory rate and body temp.

pressure wave caused by the expansion and recoil of elastic arteries

low bp in which systolic pressure is blow 100 mm Hg

• 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

automatic adjustment of blood flow to each tissue in proportion to its requirements at ay given time

• 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

• hypovolemic shock: results from large scale blood loss
• vascular shock: poor circulation resulting from extreme vasodialation
• cadiogenic shock: heart cannot sustain adequate circulation

• pump-right and left side
• pipes- blood vessels
• plasma-water

• 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

• 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

• 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.