Practice questions lecture 7 Flashcards
Extra Qs from ppt + cassidy's practice quiz
Which refers to the volume of blood, flow rate or velocity of flow?
Flow rate
List triggers for intrinsic metabolic influences on arterioles to step in
-Decreased O2
-Increased CO2, increased acid (carbonic acid from CO2, lactic acid from glycolysis)
-Increased K+ (repeated AP’s outpace Na/K pump’s ability to restore ion gradients)
-Increased osmolarity (solutes increased during elevated metabolism)
-Adenosine release (especially in cardiac muscle)
What is histamine and where is it stored?
Paracrine stored in connective tissue and in circulating WBCs
What does histamine do to arterioles?
Vasodilates them (chemical intrinsic control)
Stretch, stress, and temperature all influence what?
Intrinsic control of arterioles
Describe neural control of arterioles
NE released from sympathetic nerve endings binds to A1-adrenergic receptors on smooth muscle
does not apply to cerebral arterioles
What two types of muscles have powerful local vasodilation mechanisms that allow them to overpower generalized sympathetic vasoconstriction?
Skeletal and cardiac muscles
The main region of control over arterioles is where?
Cardiovascular control center in medulla of brain stem
What is the integration center for blood pressure regulation?
Cardiovascular control center in medulla of brain stem
Which binds with both B2 and A1 receptors, norepinephrine or epinephrine?
Epinephrine
Which promotes vasodilation, B2 or A1 receptors?
B2
What hormone is triggered by the hypothalamus to increase water retention of kidneys, affecting water balance?
Vasopressin
What hormone secreted by the kidneys regulates salt balance as part of renin-angiotensin-aldosterone system?
Angiotensin II
True or false: All capillaries have no carrier-mediated systems
False; carrier-mediated systems present only in brain capillaries
Skeletal muscle and what tissue have similar capillary permeability?
Lung tissue
Ions, glucose, amino acids, but not proteins, can pass through water-filled pores in capillaries where?
Lung tissue and skeletal muscle
Where do capillaries allow lipid soluble materials like O2/CO2 to pass through lipid membrane?
Lung tissue and skeletal muscle
What capillaries have similar permeability to that of the kidneys?
Intestines
Where do capillaries have discontinuous endothelial cells?
Liver
What is lymph?
Interstitial fluid once it’s inside the lymphatic system
Lymph vessels empty into venous system near blood entering where?
right atrium
What is the lymph pump?
Smooth muscle of lymph vessels become distended with lymph and forcefully contract
Lymph vessels lie between what muscles?
Skeletal
What two things does lymph return to circulation?
IF and proteins
What does lymph transport?
Digested fats
What do lymph nodes contain?
Phagocytes
List the 4 groups of causes of edema (IF accumulation)
1) Reduced concentration of plasma proteins.
2) Abnormally increased capillary wall permeability.
3) Increased venous pressure.
4) Unable to return IF to circulation.
True or false: venules have little tone and resistance
True
Describe veins
Large radius, little resistance, thin walls, less smooth muscle, stretchable
Define venous return
Volume of blood per minute entering each atrium from the veins
What two things increase with sympathetic vasoconstriction of veins?
EDV and CO are increased
Where are vessels subject to pressure from weight of the overlying column of blood?
Below heart level
Paraphrase the 2 ways veins counter gravity
1) Sympathetic vasoconstriction is triggered by decreased MAP when standing up
2) Contractions in skeletal muscle break up blood column
How does cardiac suction help venous return?
Atrial pressure is below 0 mmHg during ventricular contraction (suction force) which exerts a vein-to-atria-to-ventricle pressure gradient
How does the respiratory pump help with venous return?
Pressure in chest cavity is slightly less than atmospheric pressure, veins in lower limbs have normal pressure, so pressure gradient helps.
1) What is the pressure reservoir of the circulatory system?
2) What is the blood reservoir of the circulatory system?
1) Arteries
2) Veins
Where is elastin found?
Larger arteries
What is the main driving force for propelling blood to the tissues?
MAP
What are the two main factors of MAP?
Cardiac output (CO) and TPR
How do you calculate MAP?
Diastolic pressure + 1/3rd pulse pressure
What two things determine cardiac output (CO)?
Heart rate and stroke volume
________________________ increases with increased venous return
Stroke volume
What determines how much blood is pumped by the heart?
Blood volume
What affects blood volume?
Balance between plasma and IF, salt and water balance, and hormones
What affects blood viscosity the most?
RBCs
What two things does TPR depend on?
Radii of all arterioles and blood viscosity
True or false: Arteriolar radius is intrinsically and extrinsically controlled
True
All of the types of short-term regulation of MAP are ultimately adjusting what two factors?
CO and TPR
What causes long term adjustments to MAP?
Adjusting salt and water balance via urine output and thirst
The baroreceptor reflex involves the carotid sinus and aortic arch (mechanoreceptors) constantly firing AP’s, which _____________ in frequency with rising MAP
increase
What are sensitive to O2 and CO2 and can influence respiratory activity?
Carotid and aortic artery chemoreceptors
What blood pressure reflexes regulate salt/water balance?
Left atrial volume receptors and hypothalamic osmoreceptors
What governs cardiovascular responses associated with certain emotions and behaviors like blushing, anger, fear?
Cerebral cortex-hypothalamic pathway
Hypothalamic control over _____________________ helps with temperature regulation
cutaneous arteries
Constant HTN damages vessels, predisposing to ___________________, which narrows lumens, which increases TPR, which further elevates BP
atherosclerosis
What happens when the heart works harder to pump blood against resistance [due to HTN]?
Left ventricular hypertrophy
Why does systolic heart failure happen due to HTN?
Heart weakens and becomes unable to pump against elevated pressure
HTN can cause:
Strokes caused by rupture of ________________ arteries
Heart attacks caused by rupture of _______________ arteries
1) cerebral arteries
2) coronary arteries
HTN can lead to vessel damage throughout the body that can cause kidney failure and loss of what sense?
Vision
Neurally defective vasoconstrictor tone is what type of shock?
Neurogenic
When blood pressure falls so low that tissue demands are not met, this is called what?
Circulatory shock
Excess vomiting can cause what type of circulatory shock?
Hypovolemic
Septic and anaphylactic shock are both what type of circulatory shock?
Vasogenic
What two types of shock are due to widespread vasodilation?
Neurogenic and vasogenic
What two types of shock are due to decreased cardiac output?
Cardiogenic and hypovolemic
If the difference in pressure of blood flow increases, what change to the flow rate of blood would there be?
Increased
How is flow rate measured?
Difference in pressure gradient over resistance of blood vessel
Difference in pressure gradient over resistance of blood vessel
BP
What is the heart’s ventricular pressure during diastole?
0mmHg
What measures the average blood pressure throughout the cardiac cycle?
MAP
What is the critical MAP level in which the body cannot sustain for longer than 1 minute before organs are not receiving enough oxygen?
50
What two factors are responsible for vascular tone?
1) Sympathetic fibers supplying NE
2) Voltage gated Ca+ channels
What is the most well known endothelial vasoactive paracrine?
Nitric oxide
When blood flow resumes after a tourniquet is removed, how does it relate to its baseline blood flow?
Faster
What two things trigger histamine release?
Tissue injury
Allergic rxns
What are 3 roles of sympathetic fibers as part of extrinsic arteriole control?
1) Controlling MAP by adjusting peripheral resistance in the body
2) Promote vasoconstriction
3) Norepinephrine binding to A1-adrenergic receptors on smooth m.
Where is the main region for cardiovascular control in the brain?
Medulla
Within the adrenal medulla for hormonal extrinsic control of arterioles, _____ combines with A1 receptors for vasoconstriction
NE
What is the speed with which blood flows through a given circulatory segment?
Velocity of flow
Where do capillaries have the largest fenestrations and gaps in their endothelial cells?
Liver
Where do lymph vessels empty into?
Venous system near right atrium
________ concentration of plasma proteins is a reason for edema/ excess interstitial fluid accumulation.
Reduced
What vessel has a large radium, little resistance, and thin walls with less smooth muscle?
Veins
What is venous blood pressure normally at?
17mmHg
Pressure in the chest cavity is _____________ than atmospheric pressure.
slightly less
