Ch 19 Blood Vessels Flashcards
3 major vessels
Arteries capillaries veins
Where do arteries carry blood?
Away from heart
Veins carry blood where?
Toward the heart.
Arteries carry what kind if blood in systemic circulation?
Oxygenated blood
Veins carry what kind of blood in the systemic circulation?
Oxygen poor blood
In the pulmonary circulation the arteries carry blood
Away from the heart and oxygen poor
In the pulmonary circulation, the veins carry blood
From the lungs to the heart
Oxygenated
Walls of the blood vessels have how many layers?
3 tunics
Lumen
Blood containing space
Vasoconstriction/vasodilation occurs in which tunic?
Tunic media
Chief functioned the tunic media
Maintain blood pressure
Elastic arteries
Thick
Neat the heart
Elastin
Swiss cheese appearance between layers of smooth muscle cells
Muscular arteries
Diver blood to specific body organs
Vasoconstriction
Arteriolar
Smallest arteries
3 types if capillaries
Continuous
Fenestrated
Sinusoidal
Continuous capillaries are where?
Skin and muscle
Intracellar clefts
Membranes
Allows limited passage of solutes and fluids.
Fenestrated capillaries
Permeable to fluids and small solutes
Fenestrated capillaries are where?
Sm. intestine
Endocrine organs
Sinusoids
Leaky capillaries
Where are sinusoid all capillaries found?
Liver
Bone narrow
Spleen
Adrenal medulla
Hepatic macrophages
Kupferr cells
Remove and destroy contained bacteria
Capillary beds
Network of capillaries
Microcirculation
Flow if blood from the arteriole to a venule
Capillary bed consists if 2 vessels
Vascular shunt
True capillaries
Exchange vessels
Route of capillary beds
Terminal arteriole
Metarteriole
Thoroughfare channel
Post capillary venule
Precapillary sphincter
Surrounds the root of a true capillary to regulate blood flow into the capillary
When the capillaries sphincter is open what happens?
Blood flows through capillaries and takes Orr in exchanges with tissue cells
When the precapillary sphincter is closed, what happens?
Blood flows through the shunts and biopasses tissue cells
Vascular anastomoses
Vascular channels that unite and form inner connections
Arterial anastomoses
Arteries supplying the same area as vascular anastomoses
Collateral channels
Alternate pathway for blood to reach a region
Arterial anastomoses occurs where?
Joints
Abdominal organs
Brain
Heart
Arteries that do not anastomoses
Retina
Kidneys
Spleen
Blood flow
Volume of blood flowing through through a vessel, organ, entire circulation
BP
Force per unit area excerpted on a vessel wall by the contained blood
Resistance
Opposition to flow
Measure if the amount of friction blood encounters as it passes through the vessels
Blood viscosity
Internal resistance to flow
Total blood vessel length
Relationship between total blood vessel length and resistance
What 2 factors does arterial bp reflect?
How much the elasric arteries close to the heart stretch
The volume of the blood forced onto them at any time
Systolic pressure
Left ventricle contracts and the pressure peaks as it goes into the aorta
Diastolic pressure
Aortic valves closes
Aortic pressure drops to the lowest
Pulse pressure
Difference between systolic and diastolic pressures
Increased SV and faster blood ejection=
Increases contractility
MAP
Mean arterial pressure
Pressure that propels the blood to the tissues
Formula for MAP
MAP=diastolic pressure + pulse pressure/3
Respiratory pump
Pressure in the chest decreases thoracic veins to expand and speeds blood entry into right atrium
Muscular pump
Keeps blood from flowing back as the skeletal muscles contract and relax
Short-term control
Mediated by the nervous system
Counteract fluctuations in blood pressure by altering resistance
Brutal controls of peripheral resistance are directed at 2 goals
Maintaining adequate MAPLtwring blood distribution to respond to different demands of various organs
Most neural controls operate by reflex arcs by…
Baroreceptors
Sometimes inputs from chemoreceptors will
Influence the neural control mechanism
Vasomotor center
Neural center that oversees changes in the diameter of blood vessels
Cardiovascular center
Integrates bp control by alternating CO and blood vessel diameter
Vasomotor fibers
vasomotor center Transmits impulses at a steady rate along sympathetic efferents
Vasomotor tone
Arterioles are in a state if moderate constriction
vasomotor activity is modified by inputs from
Baroreceptors
Chemoreceptors
Higher brain centers
Baroreceptors
Neural receptors
Paracrines
Serve to match the amount of blood flow to the metabolic need of a particular tissue
Adrenal medulla hormones
Release norepinephrine and epinephrine to the blood to the sympathetic response
Angiotensin II
An enzyme that results from renin
Arterial natriuretic peptide ANP
Hormone that the heart produces which causes blood volume and blood pressure to decline
Anti diuretic hormone ADH (vasopressin)
Stimulates the kidneys to conserve water
Long term controls of bp counteract fluctuations in bp by altering blood volume.
altering blood volume.
Renin angiotensin mechanism
Indirect renal mechanism
Aldosterone
Hormone that enhances renal absorption
Tissue perfusion
Blood flow through body tissues
Tissue perforation is involved in
Divert of oxygen and nutrients to tissue cells
Removal if waste from tissue cells
Gas exchange in lungs
Absorption of nutrients from digestive tract
Urine formation
Autoregulation
Automatic adjustment of the blood flow to each tissue
Nitric oxide
Vasodilator
Releases when vasodilation is needed
Endothelial
Vasoconstrictor
4 routes across capillaries for different molecules
Lipid-soluble molecules diffuse through a lipid bilayer
- fluid-filled intercellular capillary clefts
- fenestrations
- lg molecules transported in pinocytotic vesicles
Hydrostatic pressure
Force excerted by a fluid pressing against the wall.
Colloid osmotic pressure
Created by the presence Ina fluid of lg nondifusable molecules
Circulatory shock
Blood vessels are I adequately filled and blood cannot circulate normally.
Hypovolemic shock
Loss of blood
Vascular shock
Blood volume normal but circulation is poor due to abnormal expansion of the vascular bed caused by extreme vasodilation
Arteries run deep and veins run deep and superficial
deep and superficial