Chapter 20- Blood Vessels Flashcards
Summary of where blood vessels are carried:
Heart -> arteries -> arterioles -> metarteriole -> capillary -> venules -> veins -> heart
Arteries:
vessels carrying blood ___ from the heart
usually this blood is ____
large diameter: ____ arteries and ____ arteries
3 layers of tissue
vessels carrying blood AWAY from the heart
usually, this blood is OXYGENATED
large diameter: ELASTIC arteries and MUSCULAR arteries
3 layers of tissue
Elastic arteries
located near heart
considered conducting
Muscular arteries
considered distributing (more responsive to vasoconstriction)
3 distinct layers of arteries:
Tunica intima
Tunica media
Tunica externa
Tunica Intima: deepest tunica consisting of ______ = single layer of epithelial cells lining the ___ and _____, and an _____ _____ ______
deepest tunica consisting of ENDOTHELIUM = single layer of epithelial cells lining the HEART and VESSELS, and an INTERNAL ELASTIC MEMBRANE
Tunica Media
usually thickest layer consisting of SMOOTH MUSCLE and in some vessels, an EXTERNAL ELASTIC MEMBRANE
Tunica Externa
elastic and collagen fibers
The alternate expansion and recoiling of elastic arteries after each ventricular systole of the left ventricle creating a pressure wave that travels through the arteries
Pulse
Common pulse locations
neck- carotid artery
wrist- radial artery
groin- femoral artery
Arterioles and metarterioles
small arteries
connects arteries with capillaries
important in regulation of blood flow to the capillaries
Capillaries:
a. Composed of single layer of ______
b. Lumen size large enough to allow one ___to flow per unit time - allows for ______________;_______
c. exist in capillary ___ (capillary networks) - when tissue needs are low, blood will flow only through a ___ portion of the network. When needs increase, the entire capillary bed is full of blood. Regulated by: _________________________________. Blood can also be shunted through the capillary bed going from the metarteriole to a _______ _____
a. endothelium
b. RBC- allows for exchange of nutrients/wastes; decreased velocity
c. bed, small
Regulated by: precapillary sphincters
thoroughfare channel
Precapillary sphincters
controls blood flow through the capillary bed
What controls blood flow to the capillaries?
arterioles and metarterioles
Capillaries are found in all tissues except:
lens, cornea, epithelium, cartilage
3 main types of capillaries and where they’re found:
- Continuous (muscle, nervous)
- Fenestrated (kidney, intestines)
Sinusoidal (liver, bone marrow)
Capillaries are the site of material moving in and out of the circulatory system. There is gas exchange occurring at the tissue level and there is ____ _____ of large amounts of ions, proteins, other nutrients and water.
The bulk flow ___ of the capillary occurs at the arteriole end. At the venule end, the fluid moves ____ the capillary from the tissue spaces. In health, approximately 85% of the fluid at the arteriole ends of the capillaries is reabsorbed at the venule end. Some of the escaped fluid and proteins will be returned to the blood via the lymphatic system. Approximately 20 liters of fluid filters out of the capillaries each day, 17 liters will be reabsorbed by the capillary and 3 liters enter the lymphatics. The _______ ______ forces fluid out of the capillary while _____ _____ helps to return fluid back to the vessel.
. Capillaries are the site of material moving in and out of the circulatory system. There is gas exchange occurring at the tissue level and there is BULK FLOW of large amounts of ions, proteins, other nutrients and water.
The bulk flow OUT of the capillary occurs at the arteriole end. At the venule end, the fluid moves INTO the capillary from the tissue spaces. In health, approximately 85% of the fluid at the arteriole ends of the capillaries is reabsorbed at the venule end. Some of the escaped fluid and proteins will be returned to the blood via the lymphatic system. Approximately 20 liters of fluid filters out of the capillaries each day, 17 liters will be reabsorbed by the capillary and 3 liters enter the lymphatics. The HYDROSTATIC PRESSURE forces fluid out of the capillary while ONCOTIC PRESSURE helps to return fluid back to the vessel.
Edema
an abnormal increase in interstitial fluid
Hydrostatic pressure
pushes fluid out of capillary
Oncotic pressure
pulls fluid back into capillary
What helps pull the fluid back into the capillary?
Albumin
If bulk flow is impaired, an edema results. What are 4 possible causes of edema?
- Blocked lymphatics
- Increased hydrostatic pressure
- Decreased oncotic pressure
- Increased capillary permeability
Veins
- carries blood towards the heart
- usually carries deoxygenated blood
- 3 tunicas which are very thin with a large lumen
There is no ____ _____ in the tunica interna, meaning they stay dilated. This is also why you wouldn’t measure pulse or blood pressure. However, they’re great for _____ ____
elastic membrane
drawing blood
3 Tunicas of veins:
- Tunica interna: endothelium
- Tunica media: smooth muscle (not as much as arteries though)
- Tunica externa: thickest, mainly composed of collagen
Veins/Venules have a ___ ____ ____. The blood reservoir is __%, meaning veins are where the _____ of blood is found.
Remember: when the blood in these reservoirs are stored, it ____ _____ _____
low pressure system
65%
majority
it never stops flowing
Venules drain the ____ ___ and take blood to the ____. It’s anatomy varies according to location but it’s most similar to _____
capillary beds
veins
capillaries
3 factors aiding in blood flow through the veins:
Valves
Skeletal muscle contraction
Breathing
The __________ center located in the ____ ______ will control the rate of the heart as well as the ______ ____
The CARDIOVASCULAR center located in the MEDULLA OBLONGATA will control the rate of the heart as well as the VESSEL DIAMETER
Vasoconstriction
Vasodilation
When the vessels’ diameters decrease
When the vessels’ diameters increase
What layer is affected in vasoconstriction/dilatation?
Tunica media
What vessel will have the greatest effect on vasoconstriction/vasodilation?
artery
venule
arteriole
vein
arteriole
Changing diameter affects _______(opposes flow/amount of friction)
resistance
Vasodilation: effect on resistance, blood pressure, and blood flow
decreased resistance and blood pressure
increased blood flow
Vasoconstriction: effect on resistance, blood pressure, and blood flow
increased resistance and blood pressure
decreased blood flow
Other factors that affect flow/pressure:
include it’s effect on blood pressure and blood flow
Viscosity (increase BP, decrease BF)
Vessel length (increase BP, decrease BF)
Blood volume (increase BP)
Systolic number
Measurement of pressure in vessels when the left ventricle is contracting
(during systole)
Diastolic number
Measurement of pressure in vessels when the left ventricle is relaxing (during diastole)
Blood pressure
The pressure that is exerted by the blood as it presses on ____ walls during _______ systole and diastole.
The pressure that is exerted by the blood as it presses on arterial walls during ventricular systole and diastole
Normal reading of blood pressure
120/80 mmHg
Blood pressure is regulated by
Autonomic nervous system (sympathetic/parasympatheric)
Endocrine system
The top number is the ______ _____ pressure while the bottom number is the ______ ____ pressure
top = systolic arterial pressure
bottom = diastolic arterial pressure
The endocrine system helps regulate blood pressure, but what hormones specifically?
- Epinephrine/norepinephrine (found in medulla of adrenal gland)
- Aldosterone (mineralocorticoid)
- ADH (found in P.P)
- ANP (stands for atrial natriuretic)
Describe it’s effect on blood pressure (and volume) for each:
- Epinephrine/norepinephrine (found in medulla of adrenal gland)
- Aldosterone (mineralocorticoid)
- ADH (found in P.P)
- ANP (stands for atrial natriuretic)
- Epinephrine/norepinephrine (found in medulla of adrenal gland)
- Aldosterone (mineralocorticoid)
- ADH (found in P.P)
^^ These all increase blood pressure
Atrial Natriuretic (ANP) is the only one to decrease blood pressure, as well as blood volume
Hypotension
Low BP
If the BP is extremely low, it could cause kidney shutdown
What is a cause for low BP? Describe it.
Orthostatic- after rising rapidly, BP lowers for a moment
Hypertension:
Normally occurs when individual is physically or emotionally stressed. However, ________ _______ is constant high B/P over time and is also called the ______ _____. The person may feel fine for 10 - 20 years, but have increasing B/P. This slowly strains the heart and vessels. (140/90)
Hypertension also causes damage to the endothelial layer of the vessels leading to atherosclerosis and finally arteriosclerosis (hardening of the arteries). Hypertension is more prevalent in African Americans, _____, ______, and individuals with poor diets, obesity, and people with _____ ____
Normally occurs when individual is physically or emotionally stressed. However, PERSISTENT HYPERTENSION is constant high B/P over time and is also called the SILENT KILLER. The person may feel fine for 10 - 20 years, but have increasing B/P. This slowly strains the heart and vessels. (140/90)
Hypertension also causes damage to the endothelial layer of the vessels leading to atherosclerosis and finally arteriosclerosis (hardening of the arteries). Hypertension is more prevalent in African Americans, MALES, SMOKERS, and individuals with poor diets, obesity, and people with DIABETES MELLITUS
Problems with hypertension
Heart effects:
Vessel effects:
Heart effects: afterload
Vessel effects: elasticity
Treatments for hypertension
Low sodium diet
Diuretics
Aneurysm
Localized dilatation of an artery
Concern: it can pop/rupture
Common locations of an aneurysm
Aorta
Cerebral
Varicose Veins
Dilation of veins
Most common in pregnant women and nurses
Atherosclerosis:
Starts with _____ to the endothelium
Chemotaxis of LDL (macrophages eat becoming ___ ____)
Forms ____ of foam cells, collagen, and elastin
______ deposits in the center
Starts with INJURY to the endothelium
Chemotaxis of LDL (macrophages eat becoming FOAM CELLS)
Forms PLAQUES of foam cells, collagen, and elastin
CALCIUM deposits in the center
The beginning damage is termed ________ while the end product is ________
Atherosclerosis
Arteriosclerosis
Arteriosclerosis
End result of atherosclerosis
Vessels lose their elasticity- hardening of the arteries
Common locations of arteriosclerosis
Aorta
Coronary
Carotid
Circulatory Shock
Inadequate perfusion to the tissues
Symptoms of shock
Fast HR
Weak pulse
Cold
Pale (gingiva)
CRT is <2 secs
Low blood volume
hypovolemia
What types of shock are due to hypovolemia
Hemorrhagic shock
Plasma loss shock
Dehydration
What types of shock are due to vasodialation
Anesthesia
Anaphylactic shock
Infection
Neurogenic
