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