ch 21 - blood vessels study guide Flashcards
What is the difference between arteries and veins?
arteries:
Carry oxygenated blood away from the heart
thicker walls
smaller lumen
veins
carry deoxygenated blood towards the heart
thinner walls
wider lumen
has valves
three layers of blood vessel structure
tunica intima
tunica media
tunica externa
tunica intima
inner layer, thin layer
has a simple squamous endothelial lining, smooth muscle and an external elastic membrane
tunica media
middle layer
thicker area
made up of smooth muscle and connective tissue
tunica externa & what tissue it’s made of
outer layer
made of connective tissue
What are elastic arteries
conducting arteries located closets to the heart with more elastic in tunica media
elastic artery example
aorta
elastic vs muscular artery
muscular tissue have more muscular tissue, known as distributing arteries, medium size instead of largest size, draws blood from elastic arteries
What are arterioles and their role in vascular tree
smallest branches of arteries that lead to capillary beds
What is the role of Precapillary sphincter?
smooth muscle that help direct bloodflow into capillaries.
What are the three different types of capillaries?
continuous
fenestrated
sinusoids
continous capilalries
most common type of capillary made up of endothelial cells. cells sit close together (continuously)
fenestrated capillaries
capillaries with small pores/openings that allow larger molecules to move
sinusoids capillaries
capillaries with large gaps between endothelial cells, allowing for the easy passage of large molecules
What are varicose veins? How are they formed?
varicose veins form when valves dont work properly, causing blood to pool in the veins and become distended
the different types of Starling’s forces
hydrostatic pressure: pushes fluid out of capillaries
oncotic pressure: pulls fluid back into capillaries
net filtration pressure (NFP)
the difference between net hydrostatic pressure and the net osmotic pressure
net pressure at arterial end
NFP is 10 mmHg
net pressure at venous end
NFP is -7 mmHg
What happens to the fluid that could not be reabsorbed?
(2 options)
stays in the tissues causing swelling and water retention
lymphatic system carries back remaining tissue
Which blood vessels are called capacitance vessels or the blood reservoirs?
veins
What are the 4 forces that aid in venous return?
venous valves
skeletal muscular compression of veins
venoconstriction
respiratory pump
Which vessels are called resistance vessels?
arterioles bc they control blood flow and pressure by varying their diameter
What is the relationship between blood pressure, blood flow and resistance?
Blood flows from areas of high pressure to areas of low pressure
The heart generates pressure, and this pressure difference drives blood flow through the circulatory system
If resistance increases (e.g., due to narrowed blood vessels), the heart needs to work harder to maintain blood flow, potentially leading to higher blood pressure.
What is the relationship between the diameter of the vessel and the resistance?
In blood vessels, most of the resistance is due to vessel diameter. As vessel diameter decreases, the resistance increases and blood flow decreases
How will the resistance change if the vessel diameter is halved and how will it change if diameter is doubled?
decreased diameter: more blood contacts the wall, increasing friction and thus decreasing blood flow
increased diameter: means wider vessel, less blood touches vessel wall, reducing friction and thus increasing blood flow
How is blood flow auto-regulated in various organ systems?
local blood flow is regulated by adjustments in peripheral resistance, while the cardiac output stays the same
What role does sympathetic and parasympathetic play on the blood vessels?
- Blood vessels are supplied by the sympathetic nervous system, which can cause constriction and is involved in increasing blood pressure and modulating blood flow
- The parasympathetic nervous system is involved in dilating blood vessels that lead to the gastrointestinal tract and increasing blood flow.
what are baroreceptors
respond to changes in blood pressure
if blood pressure is low: detect less stretch
if blood pressure is high: detect more stretch
where are baroreceptors found
found in walls of carotid sinuses, aortic arch and wall of right atrium
aortic baroreceptors trigger aortic reflex
What is carotid sinus reflex?
helps regulate your blood pressure
When pressure increases in the carotid sinus sensors send signals to slow your heart rate and lower blood pressure
If pressure drops, the opposite happens—your heart rate increases to raise blood pressure.
chemoreceptor function
respond to changes in chemical composition, particularly pH and oxygen and carbon dioxide levels
Where do you find chemoreceptors in human body?
carotid and aortic bodies & medulla oblongata
carotid and aortic bodies chemoreceptors function
monitor blood pH, CO2 and oxygen levels
medulla oblongata chemoreceptors function
monitor CO2 levels of cerebrospinal fluid
what is ANP
atrial natriuretic peptide: released in response to high blood pressure
it promotes vasodilation and creases blood volume by blocking release of aldosterone and ADH
How do pulmonary vessels respond to hypoxic situations?
Angionegesis: formation of new blood vessels are created in response to hypoxia
hypertension
high blood pressure
greater than 140/90 mm Hg
4 stages of hypertension
elevated: 120-129/80 mm Hg
stage 1: 130-139/89 mm Hg
stage 2: 140/90 mm Hg
hypertensive: 180/120 mm Hg
the 5 different types of shock (CHANS)
cardiogenic
hypovolemic
anaphylactic
septic
neurogenic
cardiogenic shock
shock due to heart problems
hypovolemic shock
shock caused by too little blood volume
anaphylactic shock
shock caused by allergic reaction
septic shock
shock due to infection
neurogenic shock
shock caused by damage to nervous system
What is hepatic portal system?
connects the capillary beds of digestive organs to the sinusoidal capillaries of the liver
the various blood vessels included in hepatic portal system (GICSS)
inferior mesentric vein
splenic vein
superior mesentric vein
gastric veins
cystic veins
inferior mesentric vein
drains part of large intestine
splenic vein
drains spleen
superior mesentric vein
drains stomach, part of large intestine
gastric veins
drains stomach
cystic veins
drains gallbladder
adult vs fetal circulation
fetal:
blood flows from fetus to palcenta via umbilical arteries
blood returns to placenta via umbilical vein that drains into ductus venosus
structures that allow fetal circulation: foramen ovale and ductus arteriosus
In the capillaries, hydrostatic pressure (HP) is exerted by
blood pressure
The net hydrostatic pressure (HP) is the hydrostatic pressure in the __________ minus hydrostatic pressure in the __________.
capillary; interstitial fluid
Reabsorption of fluid into the capillary takes place at the arterial end or venous end of the capillary?
venous
which layer of blood vessel is amde up of smooth muscle
tunica media
Which vessels have the highest blood pressure?
arteries
Which vein is often used to collect blood from an individual?
median cubital
From which artery is a person able to feel his or her pulse?
common carotid
Which veins drain blood from the diaphragm?
phrenic vein
Small blood vessels in the tunica externa (adventitia) of a blood vessel that supply blood to the outer parts of the vessel wall are called
vasa vasorum
blood vessels correctly ranked in order of decreasing wall thickness?
artery, arteriole, metarteriole, capillary
The walls of capillaries are made of
endothelium only
Which layer of the blood vessel wall anchors it to surrounding structures?
externa
The largest arteries are the
conducting (elastic) arteries
What kind of vessel provides a bypass for a capillary bed?
thoroughfare channel
In the pulmonary circulation, blood that leaves the pulmonary trunk next enters the
left and right pulmonary arteries
Which part of the aorta is attached to the heart?
ascending aorta
The descending aorta consists of these two subdivisions.
thoracic and abdominal
The brachiocephalic veins are formed by the junction of the
axillary and cephalic veins
The axillary vein is formed by the junction of the
brachial and basilic veins
The median cubital vein joins the
cephalic and basilic veins
The inferior vena cava is formed by the junction of the
left and right common iliac veins
