Chapter 21 - Blood Vessels Flashcards
(39 cards)
name the types of blood vessels, largest to smallest.
Arteries
- arterioles
Veins
- venules
Capillaries
- Microscopic capillary networks permeate all active tissues
- Anastomosis is structure
name the 3 blood vessel structure walls, their structure, and functions.
name the 2 membranes.
what is the structure of “vessels of vessels” that are small arteries and veins in walls.
- Tunica intima (innermost) - “underwear”
- Endothelial lining (inner intima layer)
- Connective tissue layer (just outside endothelium)
*Internal elastic membrane (in arteries) - between intima and media layer - Tunica media (middle)
- Contains concentric sheet of smooth muscle in loose connective tissue (constriction and dilation)
- Encircles the endothelium (the intima) that lines the lumen (interior space) of blood vessel
*External elastic membrane - between media and externa - Tunica externa / adventitia (outer) - like an overcoat of collagen fibers.
- the larger the vessel, the larger the externa
- Anchors vessel to adjacent tissue
- Contains: collagen fibers, elastic fibers, smooth muscle cells (in veins)
*Vasa Vasorum (“vessels of vessels”) (know for exam) - Small arteries and veins in walls of externa and media
what are the differences in arteries and veins.
what are the names for vessel contraction and expansion?
- Arteries have thicker walls and higher blood pressure
- Constricted artery has small and round lumen, vein has large and irregular shape lumen
- The endothelium of a constricted artery is folded
- Arteries are more elastic than veins since they absorb pressure waves that come with each heartbeat
- Veins have valves
*vasoconstriction - contraction
*vasodilation - expansion, dilation
from heart to capillaries, arteries change.
name the types of arteries based on tunica media and give examples of each.
- Elastic arteries (conducting arteries) (know examples)
- Large vessels like pulmonary trunk and aorta
- Tunica media has many elastic fibers, few muscle cells, to even out force of blood - Muscular arteries (distribution arteries)
- Most arteries are medium sized muscular
- distribute blood to specific body parts
- Tunica media has many muscle cells - Arterioles (resistance vessels)
- Small arteries
- Little to no tunica externa. Their tunica media is thinner than tunica media of arteries
- Thin or incomplete tunica media
- Regulates blood flow from arteries to capillaries
what is an aneurysm?
A bulge in arterial wall, not broken yet, just bulging
Weak spot in elastic fibers
Pressure may rupture vessel
name the function and layers of a capillary
Function - Exchange of materials, diffuse between blood and interstitial fluid
Structure - only 2 layers: endothelial tube surrounded by basement membrane layer. Diameter is similar to that of a red blood cell
name the 3 types of capillaries and their structures.
- Continuous capillaries
- Permits diffusion of water, small solutes, and lipid-soluble materials
- Found in all tissues except epithelia and cartilage
- Have complete endothelial lying
- Specialized continuous capillaries in CNS and thymus - blood brain barrier - Fenestrated capillaries
- Have pores in endothelial lining for immediate exchange of water and large solutes
- Found in choroid plexus, endocrine organs, kidneys, intestinal tract - Sinusoids
- Gaps between adjacent endothelial cells
- Permits free exchange of water and large plasma proteins
- In Endocrine organs, bone marrow, liver, spleen
- Phagocytic cells monitor blood at sinusoids
name the sizes of veins with examples.
Small veins = venules - to capillaries
Medium-sized veins - most
Large veins - vena cava, pulmonary, etc.
All veins have semilunar valves for one way movement, fighting against gravity. compression of veins pushes blood toward heart
what is the distribution of blood in percentage for the heart / arteries / capillaries and the venous system?
Heart, arteries, and capillaries = 30-35% of blood volume
Venous system = 65-70%
- 1/3 of venous blood is in large venous networks of the liver, bone marrow, and skin
define blood pressure, capillary hydrostatic pressure, and venous pressure.
Blood Pressure - arterial pressure (mm Hg)
Capillary hydrostatic pressure - pressure within the capillary beds
Venous pressure - pressure in the venous system
arterial blood pressure. go through slide…
what is normal bp?
what is pulse pressure?
what is mean arterial pressure (MAP)?
Systolic pressure - peak arterial pressure during contraction
Diastolic pressure - minimum arterial pressure at end of ventricular diastole
Pulse pressure - difference between systolic and diastolic pressure
Mean arterial pressure (MAP) - diastolic pressure + 1/3 of pulse pressure
Hypertension
Hypotension
*normal bp is 120/80
Venous pressure.
Determines the amount of venous return in 1 minute
Low effective pressure and low resistance in venous system
Blood return is assisted by
- Skeletal muscular compression of veins
- The respiratory pump - pressure changes in thoracic cavity
Cardiovascular center and CNS activities - go through slide…
endocrines have short-term and long-term effects
Thought processes and emotional states can elevate blood pressure by cardiac stimulation and vasoconstriction
Epinephrine and Norepinephrine stimulate cardiac output and peripheral vasoconstriction
(blood pressure rises with adrenaline, maybe why you feel faint with a blood pressure drop after stressful event)
what is Antidiuretic Hormone (ADH) and what does it do?
Released by neurohypophysis (in pituitary lobe)
Elevates blood pressure
Reduces water loss at kidneys
ADH responds to
- Low blood volume
- High plasma osmotic concentration
- Circulating angiotensin II
what is Angiotensin II and what does it do?
- Released in response to a decrease in renal blood pressure
- Stimulates Antidiuretic Hormone (AHD) secretion, Aldosterone production, thirst, cardiac output and peripheral vasoconstriction
what is Erythropoietin (EPO) and what does it do?
- Hormone to stimulate RBC production, released by kidneys
- Responds to low blood pressure or low oxygen content in blood
- Stimulates vasoconstriction
what are Natriuretic Peptides and what do they do?
name the 2 main types.
(Hormone proteins that regulate the cardiovascular system and are produced by the heart, blood vessels, brain, and kidneys)
- Atrial natriuretic peptide (ANP)
- Produced by cells in right atrium
- Brain natriuretic peptide (BNP)
- Produced by ventricular muscle cells
Respond to excessive diastolic stretching
Reduces blood volume and blood pressure by several means…
some organs have separate mechanisms to control blood flow. read through these for the brain, heart, and lungs, which are highly demanding organs.
- Brain
(when peripheral vessels constrict, cerebral vessels dilate to normalize blood flow
- CVA is a stroke - blockage or rupture in cerebral artery, stops blood flow - Heart
- Lactic acid, low oxygen levels, and epinephrine dilate coronary vessels to increase coronary blood flow, reduces blood flow elsewhere
- Epinephrine also increases HR and strengthens contractions
- Blood flow blockage can cause angina, tissue damage, heart failure, death
- *In heavy exercise, cardiac output increase to maximum about 4x resting level (just know this) - Lungs
- Regulated by oxygen levels in alveoli
- High oxygen - vessels dilate
- Low oxygen - vessels constrict
Exercise and cardiovascular disease. read through…
- Cardiac output rises in response to venous return (Frank-Starling principle) and atrial stretching
- Moves low-density lipoproteins to liver → bile → excreted
- Slows the formation of plaques
- Reduces the risk of MI and coronary artery disease
- Speeds recovery after a heart attack
Cardiovascular response to hemorrhaging. read through for short-term, long-term, and shock.
- Entire cv system adjusts blood pressure and blood volume
Short-term elevation of blood pressure
- Carotid and aortic reflexes - increase cardiac output, heart rate, and cause peripheral vasoconstriction
- Sympathetic nervous system - further constricts arterioles, improves venous return
- Hormonal effects - increase cardiac output and vasoconstriction
Shock
- Failure to restore blood pressure results in shock, short-term
Long-term restoration of blood volume
- Recall of fluids from interstitial space
- Aldosterone and ADH promote fluid retention and reabsorption
- Thirst increases
- EPO stimulates rbc production
Fetal Circulation
Best to watch Khan Academy video…
Placenta > oxygenated blood through *Umbilical vein to either liver or through *ductus venosus to Inferior VC.
> now a mix of oxygenated / deoxygenated blood > right atrium and left atrium through *foramen ovale > right ventricle to lungs (but lungs are filled with fluid and have high resistance, so then do not accept or return much blood), back to left atrium and left ventricle to aorta to body / or straight from left atrium to left ventricle to aorta to body.
*the bypass connecting pulmonary trunk to aorta is the ductus arteriosus (artery to artery)
> from body, deoxygenated blood returns through *umbilical artery to placenta
Before Birth
- Fetal lungs are collapsed, oxygen through placenta
Cardiovascular changes at birth
- Newborn breathes air, lungs expand
- Pulmonary vessels expand
- Reduced resistance increases blood flow
- Rising oxygen causes ductus arteriosus constriction
- Rising left atrium pressure closes foramen ovale
- Pulmonary circulation provides oxygen
what is blue baby?
what is Tetralogy of Fallot?
what is Ventricular septal defect?
what is Atrioventricular septal defect?
what is Transposition of the Great Vessels?
Blue Baby - defects in the heart or lungs, where a baby’s body becomes blue due to lack of sufficient oxygen.
Tetralogy of Fallot
- Narrow pulmonary trunk, incomplete interventricular septum, aorta is not in right spot, both ventricles enlarged
Ventricular septal defect
- Opening in interventricular septum
Atrioventricular septal defect
- Both atria and ventricles are incompletely separated, common with down syndrome
Transposition of the great vessels
- aorta, pulmonary attaching to different than regular vessels
Effects of Aging on Cardiovascular System
- blood, heart, and blood vessels
read through…
Blood changes -
- Decreased hematocrit
- Thrombus
- Pooling of blood in legs due to valve deterioration
Heart changes -
- Reduced maximum cardiac output
- Changes in nodal and conducting cells
- Reduced elasticity of cardiac skeleton
- Progressive atherosclerosis
- Replacement of damaged cardiac muscle cells by scar tissue
Blood vessels changes -
- Arteries become less elastic → aneurysm
- Calcium deposits on vessel walls → stroke or infarction
- Lipid deposits in tunica media and calcium salts can form atherosclerotic plaques
know the pulmonary arteries vs pulmonary veins
know the aorta, superior vena cava, and inferior vena cava, and pulmonary trunk
