Blood Vessels BV Types A Arteries carry blood

Blood Vessels (BV)

Types A. Arteries – carry blood AWAY from the heart 1. 3 layers surrounded by a central lumen 2. Elastic and contractile 3. Can vasoconstrict (close) and vasodialate (open)

B. Arterioles - connect arteries to capillaries C. Capillaries - connect arterioles to venules

1. Capillaries are the place where gases, nutrients and wastes are exchanged between the blood and cells 2. Single cell layer walls with tiny holes called fenestrae

D. Venules - connect capillaries to veins E. Veins - carries blood TOWARDS the heart - blood reservoirs

Veins 1. Flexible: wider lumen than an artery; thinner walled 2. Contain valves to prevent backflow

3. Muscle contractions in the limbs squeeze to help move venous blood back to the heart – hard because flow is opposed by gravity

Circulation A. Factors that determine blood flow (amount of blood that passes through a vessel in a given amount of time) https: //www. youtube. com/watch? v=q. H 4 i 5 NOw 4 U 0 1. Blood pressure BP- the push of the blood on the wall of a BV- directly proportional (more BP, faster blood flow and vice versa) https: //www. youtube. com/watch? v=q. Wti 317 qb_w

2. Resistance - friction between blood and BV caused by blood viscosity, BV length, and BV diameter- indirectly proportional (more resistance, slower blood flow and vice versa)

B. Factors that affect arterial BP 1. Cardiac output - amount of blood pumped out the left atrium each minute 2. Blood volume – how much blood there is

3. Peripheral resistance - in arterioles, capillaries, venules

C. Regulation of blood pressure (BP) 1. BP is regulated by the vasomotor center in the medulla oblongata of the brain 2. The vasomotor center controls the diameter of the BV’s. Vasoconstriction increases BP, while vasodilation decreases it.

3. Baroreceptors, BP sensitive neurons, are located in the aorta and other large arteries. They send info to the brain and vasomotor center about the BP. 4. Chemoreceptors, neurons sensitive to chemicals, are located in the aortic arch. They respond to low levels of oxygen and high levels of CO 2

5. Higher brain – emotions also affect BP 6. Hormones a. Epinephrine, norepinephrine and rennin (from the kidney) increase BP b. Alcohol, histamines and ANP all decrease BP

7. Autoregulation – affects BP by responding locally to a stimulus. EX: hot, cold, low O 2

D. Capillary Exchange 1. Has the slowest rate of blood flow

https: //www. youtube. com/watch? v=pwml. P 1 h. LJf 0 https: //www. youtube. com/watch? v=c. QWUu. Uw 9 s https: //www. youtube. com/watch? v=4 y. BMY 9 Wj 7 z 0

2. Forces a. Hydrostatic pressure - pressure of the blood inside the capillaries at the arteriole end to leave the capillary and enter the interstitial fluid b. Osmotic pressure - caused by dissolved solutes inside the interstitial fluid. More solutes = more pressure. Pushes interstitial fluid out from around the cells into the blood of the capillary near the venule end. c. Filtration - fluid movement from capillaries to interstitial fluid at the arteriole end, Caused by hydrostatic pressure d. Reabsorption - fluid movement from interstitial fluid to the capillaries at the venule end. Caused by osmotic pressure

E. Factors that aid venous blood return 1. Heart pumping 2. Valves 3. Skeletal muscle contraction/ breathing https: //www. youtube. com/watch? v=JA 0 Wb 3 gc 4 m. E

Checking Circulation A. Pulse - contraction of an artery 1. Normal is 75 beats per minute/ range 65 -80 2. Tachycardia is an abnormally fast pulse, while bradycardia is abnormally slow

B. BP – blood pressure – the pressure of the blood against the inner walls of the blood vessels 1. Taken by a sphygmomanometer

(a) Systolic BP- 1 st sound- caused by the ventricle pumping. Indicates the strength of the pump – how hard the heart is beating (b) Diastolic BP- the BV resistance – indicates the cleanliness of the vessels 2. Normal - Male 120/80 Female 110/70

Shock A. Occurs when the cardiovascular system cannot deliver sufficiently due to inadequate cardiac output (CO) B. Results in cell death

C. Symptoms 1. Low BP 4. Clammy, cold skin 2. Reduced urination 5. Altered mentality 3. Thirst 6. Naseau 7. Sweating 8. Tachycardia

Circulatory Routes A. Systemic from left ventricle, out to body and back to the right atrium / to bring oxygen and nutrients to the cells and pick up CO 2 and wastes B. Pulmonary from right ventricle to lungs and back/ to reoxygenate blood

-- Major arteries Aorta, Brachiocephalic trunk, Subclavian, Carotid, Femoral, Iliac, Pulmonary

-- Major Veins Brachiocephalic trunk, Femoral, Jugular, Iliac, Pulmonary, Subclavian, Vena cava

C. Cerebral - the flow of blood at the midbrain, in the circle of Willis D. Hepatic Portal - venous blood from the GI tract to the liver (gets monitored) to inferior vena cava

E. Fetal - between mother and fetus via the placenta