Upgrade to remove ads
Only $2.99/month

Physiology Exam 2

Terms in this set (79)

Tunica intima
innermost layer and contains endothelium: runs uninterrupted through entire cardiovascular system
Internal, external elastic lamina
present only in arteries
Tunica media
Contains smooth muscle fibers (vasocontriction)
Tunica externa/adventitia
Connective tissue that stabilizes blood vessels
Functions of arteries
1. Need to handle larger amounts of pressure from the heart 2. Have thicker walls, smaller lumens than veins
Elastic arteries
(conducting arteries) Includes the aorta and its principal branches; have large lumens to collect large volumes of blood from the heart
Muscular arteries
(distributing arteries) Have the largest tunica media of any blood vessel type and possess a great ability to vasocontrict; Branch excessively to deliver blood to arterioles throughout the body
Largest arterioles
Still contain all three tunics; resemble small muscular arteries
Tiniest arterioles
Simply endothelium surrounded by 1-2 fiber layers of smooth muscle
Resistance vessels
arterioles that change their diameter to allow more or less blood flow
Metabolic responses
Adjust blood flow based on specific demands of local tissue (e.g increased NO release during exercise)
Myogenic responses
Occur reflexively within smooth muscle of tunica media (e.g. increased pressure causes contraction)
Capillaries
Smallest blood vessel type (erythrocytes single file)
Continuous capillaries
Most common type; Lining does not contain pores; exchange occurs through intercellular clefts and pinocytic vessels
Fenestrated capillaries
Endothelial cells dotted with pores; more readily allows passage of fluid and larger molecules
Sinusoid capillaries
Have larger fenestrations and a discontinuous basement membrane; allow movement of entire cells through barrier
Precapillary sphincters
Bands of smooth muscle that encircle each true capillary at its orgin froma metarteriole
Metarteriole
Arises from the terminal arteriole
Thoroughfare channel
Arises from the metarteriole; retures blood to postcapillary venule
Vascular shunt
Directly connects the terminal arteriole to the postcapillary venule
Postcapillary venule
Drains blood away from capillary bed
True capillaries
Vessels of exchange; branch off the metarteriole, converge upon the thoroughfare channel
Terminal arteriole
Delivers blood to capillary bed
Venules
Smalles of vessels carrying blood back to the heart; have three tunics but are very thin
Venous valves
Ensure unidirectional blood flow (specialized foldings of the tunical intima)
Blood Flow (F)
Volume of blood moving through a vessel, tissue, orgain, or entire circulation per unit of time
Blood Pressure (BP or P)
Force exerted onto a given area of the vessel wall by the blood contained within it, measured in mmHg
Resistance (R)
Friction encounted by blood, impeding its flow
Variables the influence resistance
1. Blood viscosity
2. Blood vessel length
3. Blood vessel radius
Total peripheral resistance (TPR)
Describes forces impeding blood flow throughout the entire circulation (VEINS)
Pulse pressure
Difference between systolic and diastolic pressure
Mean arterial pressure (MAP)
Diastolic Blood Pressure + Pulse pressure/3
Muscular pump
Assists venous return; during a contraction, bulging muscles compress vein, forcing blood back towards the heart
Respiratory pump
Assists venous return; during inspiration, intrathoracic pressure decreases, drawing blood towards the thoracic cavity
Frank Starling Mechanism
Ventricular end-diastolic volume (mL) vs. Stroke volume (mL)
CO = HR x SV
equation for cardiac output
MAP = CO x TPR
equation for MAP
Chemoreceptors
Monitor oxygen, carbon dioxide, hydrogen ion contents of blood; OBJECTIVE: change cardiac output and blood pressure to meet varying metabolic needs of body
Higher Brain Centers
Cerebral cortex and hypothalamus also relay information; Communicate with the limbic system; cause of physical manifestation of emotions
Endocrine factors
Anti-diuretic hormone (ADH): aka vasopressin causes vasocontriction; thromboxane and serotonin cause vasocontriction; epinephrine and norepinephrine casuse vasoconstriction
Effect of Aging on circulation
Blood vessles stiffen and narrow due to loss of elasticity, decreased vessel compliance
Effect of Aging on circulation
Stiffened blood vessels cause heightened MAP, which further stiffens blood vessels
Effect of Aging on circulation
Increased risk of myocardial infarction (MI)
Effect of Aging on circulation
Cardio-protective estrogen effects are lost in post-menopausal women
Conducting Division
Provides passageway for air to move; warms, humidifies, and cleanses air
Respiratory Division
Provides site of gas exchange between lungs and blood
Respiratory bronchioles
Minimal smooth muscle
Alveolar ducts
Short conduits of mainly connective tissue
Alveolar sacs
Grape-like clusters of individual alveoli that opened from the alveolar ducts
Alveoli features
Structures across which gas exchange occurs; thin-walled with large lumen; provide intimate contact between inhaled air and blood in pulmonary capillaries that wrap the alveolar walls; surface area of 70 m2
Type I Alveolar Cells
Most common type; connected to a thin basement membrane with pulmonary endothelial cell on the other side (respiratory membrane)
Type II Alveolar Cells
Cuboidal cells and make and secrete surfactant
Surfactant
Reduces surface tension between water molecules lining inner alveoli surfaces
Type III alveolar cells
(alveolar macrophages); resident alveolar immune cells; scavenge microorganisms and other particles
Deoxygenated blood in the lungs
1. Pulmonary trunk 2. Pulmonary arteries 3. Lobar arteries 4. Capillary beds surrounding alveoli
Oxygenated blood in the lungs
1. Venules 2. Small veins 3. Pulmonary veins
Pressure differential
The difference in pressure between any two spaces that are occupied by a gas (or fluid), independent of whether or not the gas can move between the spaces.
Determinants of Gas pressure
1. Amount of Gas Pressure
2. Temperature
3. Volume of Space
Boyle's Law
P1V1 = P2V2
F= Change in pressure/Resistance
Equation for Flow
Atmospheric Pressure
Pressure in the atmosphere that surrounds the body
Intrapleural pressure
Pressure in the space between the visceral and parietal pleura
Intraplumonary pressure
Pressure in the alveoli
Transpulmonary pressure
Pressure differential between intrapulmonary and intrapleural pressures; represents force that tends to collapse the lungs
Tidal Volume
500 mL; Amount of air inhaled or exhaled in one breath
Inspiratory reserve volume (IRV)
3000 mL; Amount of air in excess of tidal inspiration that can be inhaled with maximum effort
Expiratory reserve volume (ERV)
1200 mL; Amount of air in excess of tidal expiration that can be exhaled with maximum effort
Residual volume (RV)
1200 mL; Amount of air remaining in the lungs after maximum expiration; keeps alveoli inflated between breaths and mixes with fresh air on next inspiration
Vital capacity (VC)
4700 mL; Amount of air that can be exhaled with maximum effort after maximum inspiration; used to assess strength of thoracic muscles as well as pulmonary function; ERV+!RV+TV
Inspiratory capacity (IC)
3500 mL; Maximum amount of air that can be inhaled after a normal tidal expiration; TV+IRV
Functional residual capacity (FRC)
2400 mL; Amount of air remaining in lungs after a normal tidal expiration; RV+ERV
Total lung capacity (TLC)
5900 mL; Maximum amount of air the lungs can contain; RV+VC
Partial Pressure
Represents the contribution of any gas in a mixture to the mixture's total pressure; Total pressure X Fraction of Gas
Diffusion of gas partial pressures in the lungs
O2 moves from air to blood; CO2 moves from blood to air
Diffusion of gas partial pressure in the tissues
O2 moves from blood to tissues; CO2 moves from tissue to blood
Right shift of oxyhemoglobin dissociation curve (bohr effect)
OXYGEN MORE TIGHTLY BOUND; High CO2, high acidity (low pH); high of 2, 3 DPG, Excercise, Increase in temperature
Left shift of oxyhemoglobin dissociation curve (Haldane effect)
OXYGEN LESS TIGHTLY BOUND; Low CO2, low acidity (high pH); low of 2, 3 DPG, No exercise, Decrease in temperature
Carbon Dioxide diffused into RBCs
97%
Carbon Dioxide dissolved into plasma
7%
YOU MIGHT ALSO LIKE...