Step 1 Buzzwords Physiology Flashcards
USMLE Step 1 Recall: Buzzwords for the Boards Second Edition (358 cards)
0
Q
Anatomical and alveolar dead spaces together constitute what space?
A
Physiologic dead space is the total dead space of the respiratory system.
1
Q
In a ventricular pacemaker cell, what phase of the action potential is affected by NE?
A
Phase 4; NE increase the slope of the prepotential, allowing threshold to be reached sooner, and increases the rate of firing.
2
Q
What three organs are necessary for the production of vitamin D3 (cholecalciferol)?
A
Skin, liver, and kidneys
3
Q
What is the effect of LH on the production of adrenal androgens?
A
LH has no effect on the production of adrenal androgens; ACTH stimulates adrenal androgen production.
4
Q
What four conditions result in secondary hyperaldosteronism?
A
- CHF
- Vena caval obstruction or constriction
- Hepatic cirrhosis
- Renal artery stenosis
5
Q
What are the five hormones produced by Sertoli cells?
A
- Inhibin
- Estradiol (E2)
- Androgen-binding protein
- Meiosis inhibiting factor (in fetal tissue)
- Antimullerian hormone
6
Q
What is the term for the negative resting membrane potential moving toward threshold?
A
Depolarization (i.e., Na+ influx)
7
Q
Does the left or right vagus nerve innervate the SA node?
A
Right vagus innervates the SA node and the Left vagus innervates teh AV node.
8
Q
How does ventricular repolarization take place, base to apex or vice versa?
A
Repolarization is from base to apex and from epicardium to endocardium.
9
Q
What is the term for any region of the respiratory system that is incapable of gas exchange?
A
Anatomical dead space, which ends at the level of the terminal bronchioles.
10
Q
What four factors shift the Hgb-Q2 dissociation curve to the right? What is the consequence of this shift?
A
Increased CO2, H+, temperature, and 2,3-BPG levels all shift the curve to the right, thereby making the Q2 easier to remove (decreased affinity) from the Hgb molecule.
11
Q
What two factors result in the apex of the lung being hypoperfused?
A
Decreased pulmonary arterial pressure (low perfusion) and less-distensible vessels (high resistance) result in decreased blood flow at the apex.
12
Q
What is the ratio of pulmonary to systemic blood flow?
A
1:!. Remember, the flow through the pulmonary circuit and the systemic circuit are equal.
13
Q
To differentiate central from nephrogenic diabetes insipidus, after an injection of ADH, which will show a decreased urine flow?
A
Central. Remember, there is a deficiency in ADH production in the central form.
14
Q
In what area of the GI tract are water-soluble vitamins absorbed?
A
Duodenum
15
Q
What wave is the cause of the following venous pulse deflections?
The rise in right atrial pressure secondary to blood filling and terminating when the tricuspid valves opens
A
V wave
16
Q
The bulging of the tricuspid valve into the right atrium
A
C wave
17
Q
The contraction of the right atrium
A
A wave
18
Q
What are the four functions of saliva?
A
- Provide antibacterial action
- Lubricate
- Begin CHO digestion
- Begin fat digestion
19
Q
When a person goes from supine to standing, what happens to the following?
Dependent venous pressure
A
Increases
20
Q
Dependent venous blood volume
A
Increases
21
Q
Cardiac output
A
Decreases
22
Q
BP
A
Decreases
Remember, the carotid sinus reflex attempts to compensate by increasing both TPR and heart rate.
23
Q
When does the hydrostatic pressure in Bowman’s capsule play a role in opposing filtration?
A
It normally does not play a role in filtration but becomes important when there is an obstruction downstream.
24
What happens to intrapleural pressure when the diaphragam is contracted during inspiration?
Intrapleural pressure decreases (becomes more negative).
25
What is used as an index of cortisol secretion?
Urinary 17-OH steroids
26
If the pH is low with increased CO2 levels and decreased HCO3- levels, what is the acid-base disturbance.
Combined metabolic and respiratory acidosis
27
What is the term that refers to the number of channels open in a cell membrane?
Membrane conductance (think conductance = channels open)
28
What are the five tissues in which glucose uptake is insulin independent?
1. CNS
2. Renal tubules
3. β Islet cells of the pancreas
4. RBCs
5. GI mucosa
29
Place in order from fastest to slowest the rate of gastric emptying for CHO, fat, liquids, and proteins.
Liquids, CHO, protein, fat
30
Is most of the coronary artery blood flow during systole or diastole?
Diastole. During systole the left ventricle contracts, resulting in intramyocardial vessel compression and therefore very little blood flow in the coronary circulation.
31
What modified smooth muscle cell of the kidney monitor BP in the afferent arteriole?
The JG cells
32
What are the three functions of surfactant?
1. Increase compliance
2. Decrease surface tension
3. Decrease probability of pulmonary edema formation
33
Name the hormone - glucagon, insulin, or epinephrine:
| Glycogenolytic, gluconeogenic, lipolytic, glycolytic, and stimulated by hypoglycemia
Epinephrine
34
Glycogenolytic, gluconeogenic, lipolytic, glycolytic, proteolytic, and stimulated by hypoglycemia and AAs
Glucagon
35
Glycogenic, gluconeogenic, lipogenic, proteogenic, glycolytic, and stimulated by hyperglycemia, AAs, fatty acids, ketosis, ACh, GH, and β-agonist
Insulin
36
Is the hydrophobic or hydrophilic end of the phospholipids of the cell membrane facing the aqueous environment?
Hydrophobic (water-insoluble) end faces the aqueous environment and the hydrophilic (water-soluble) end faces the interior of the cell.
37
What type of muscle is characterized by no myoglobin, anaerobic glycolysis, high ATPase activity, and large muscle mass?
White muscle, short term too
38
What percentage of CO2 is carried in the plasma as HCO3-?
90% as HCO3-, 5% as carbamino compounds, and 5% as dissolved CO2
39
What is the most potent male sex hormone?
Dihydrotestosterone
40
With a decrease in arterial diastolic pressure, what happens to
Stroke volume?
Decreases
41
TPR?
Decreases
42
Heart rate?
Decreases
43
What linkage of complex CHOs does pancreatic amylase hydrolyze? What three complexes are formed?
Amylase hydrolyzes α-1,4-glucoside linkages, forming α-limit dextrins, maltotriose, and maltose.
44
Does the heart rate determine the diastolic or systolic interval?
Heart rate determines the diastolic interval, and contractility determines the systolic interval.
45
On a graphical representation of filtration, reabsorption, and excretion, when does glucose first appear in the urine?
At the beginning of splay is when the renal threshold for glucose occurs and the excess begins to spill over into the urine.
46
What is the relationship between preload and the passive tension in a muscle?
They are directly related; the greater the preload, the greater the passive tension in the muscle and the greater the prestretch of a sarcomere.
47
What is the rate-limiting step in the synthetic pathway of NE at the adrenergic nerve terminal?
The conversion of tyrosine to dopamine in the cytoplasm
48
How many days prior to ovulation does LH surge occur in the menstrual cycle?
1 day prior to ovulation
49
How are flow through the loop of Henle and concentration of urine related?
As flow increases, the urine becomes more dilute because of decreased time for H2O reabsorption.
50
What is the PO2 of aortic blood in fetal circulation?
60%
51
How do elevated blood glucose levels decrease GH secretion? (Hint: what inhibitory hypothalamic hormone is stimulated by IGF-1?)
Somatotrophins are stimulated by IGF-1, and they inhibit GH secretion. GHRH stimulates GH secretion.
52
What segment of the nephron has the highest concentration of inulin? Lowest concentration of inulin?
Terminal collecting duct has the highest concentration and Bowman's capsule has the lowest concentration of inulin.
53
What type of resistance system, high or low, is formed when resistors are added in a series?
A high-resistance systems is formed when resistors are added in a series.
54
What hormones, secreted in proportion to the size of the placenta, are an index of fetal well-being?
hCS and serum estriol, which are produced by the fetal liver and placenta, respectively, are used as estimates of fetal well-being.
55
What primary acid-base disturbance is caused by an increase in alveolar ventilation (decreasing CO2 levels) resulting in the reaction shifting to the left and decreasing both H+ and HCO3- levels?
Respiratory alkalosis (summary: low CO2, low H+, slightly low HCO3-)
56
What respiratory center in the caudal pons is the center for rhythm promoting prolonged inspirations?
Apneustic center (deep breathing place)
57
What area of the GI tract has the highest activity of brush border enzymes?
Jejunum (upper)
58
What is the term to describe the increased rate of secretion of adrenal androgens at the onset of puberty?
Adrenarche
59
What period is described when a larger-than-normal stimulus is needed to produce an action potential?
Relative refractory period
60
Does T2 or T4 have a greater affinity for its nuclear receptor?
T3 has a greater affinity for the nuclear receptor and therefore is considered the active form.
61
What are the three main functions of surfactant?
1. Lowers surface tension, so it decreases recoil and increases compliance
2. Reduces capillary filtration
3. Promotes stability in small alveoli by lowering surface tension
62
What is the only important physiological signal regulating the release of PTH?
Low interstitial free Ca2+ concentrations
63
What endocrine abnormality is characterized by the following changes in PTH, Ca2+, and inorganic phosphate (Pi)?
PTH decreased, Ca2+ increased, Pi increased
Secondary hypoparathyroidism (vitamin D toxicity)
64
PTH increased, Ca2+ decreased, Pi decreased
Secondary hyperparathyroidism (vitamin D deficiency, renal disease)
65
PTH decreased, Ca2+ decreased, Pi increased
Primary hypoparathyroidism
66
PTH increased, Ca2+ increased, Pi decreased
Primary hyperparathyroidism
67
What is the amount in liters and percent body weight for the following compartments?
ECF
14 L, 33% of body weight
68
Interstitial fluid
9.3 L, 15% of body weight
69
ICF
28 L, 40% of body weight
70
Vascular fluid
4.7 L, 5% of body weight
71
Total body water
42 L, 67% of body weight
72
What hormone is secreted by the placenta late in pregnancy, stimulates mammary growth during pregnancy, mobilizes energy stores from the mother so that the fetus can use them, and has an amino acid sequence like GH?
Human chorionic somatomammotropin (hCS) or human placental lactogen (hPL)
73
What thyroid abnormality has the following?
| TRH decreased, TSH decreased, T4 increased
Graves disease (Increased T4 decreases TRH and TSH through negative feedback.)
74
TRH increased, TSH decreased, T4 decreased
Secondary hypothyroidism/pituitary (Low TSH results in low T4 and increased TRH because of lack of a negative feedback loop.)
75
TRH decreased, TSH decreased, T4 decreased
Tertiatry hypothydroidism/hypothalamic (Low TRH causes all the rest to be decreased because of decreased stimulation.)
76
TRH increased, TSH increased, T4 decreased
Primary hypothyroidism (Low T4 has a decreased negative feedback loop, resulting in both the hypothalamus and the anterior pituitary gland to increase TRH and TSH release, respectively.)
77
TRH decreased, TSH decreased, T4 increased
Secondary hyperthyroidism (Increased TSH results in increased T4 production and increased negative feedback on to hypothalamus and decreased release of TRH.)
78
What two stress hormones are under the permissive action of cortisol?
Glucagon and epinephrine
79
If the radius of a vessel doubles, what happens to resistance?
The resistance will decrease one-sixteenth of the original resistance.
80
What prevents the down-regulation of the receptors on the gonadotrophs of the anterior pituitary gland?
The pulsatile release of GnRH
81
True or false? Epinaphrine has proteaolytic metabolic effects.
False. It has glycogenolytic and lipolytic actions but not proteolytic.
82
What is the only 17-hydroxysteroid with hormonal activity?
Cortisol, a 21-carbon steroid, has a -OH group at position 17.
83
Does the oncotic pressure of plasma promote filtration or reabsorption?
The oncotic pressure of plasma promotes reabsorption and is directly proportional to the filtration fraction.
84
Why is the base of the lung hyperventilated when a person is standing upright?
The alveoli at the base are small and very compliant, so there is a large change in their size and volume and therefore a high level of alveolar ventilation.
85
Be removing Na+ from the renal tubule and pumping it back into the ECF compartment, what does aldosterone do to the body's acid-base stores?
The removal of Na+ results in the renal tubule becoming negatively charged. The negative luminal charge attracks both K+ and H+ into the renal tubule and promotes HCO3- to enter the ECF and results in hypokalemic alkalosis.
86
What hormone causes contractions of smooth muscle, regulates interdigestive motility, and prepares the intestine for the next meal?
Motilin
87
What two vessels in fetal circulation have the highest PO2 levels?
Umbilical vein and ductus venosus (80%)
88
How many days prior to ovulation does estradiol peak in the menstrual cycle?
2 days prior to ovulation
89
What serves as a marker of endogenous insulin secretion?
C-peptide levels
90
What is the term for the total volume of air moved in and out of the respiratory system per minute?
Total ventilation (minute ventilation or minute volume)
91
What is the renal compensation mechanism for alkalosis?
Increase in urinary excretion of HCO3- shifting the reaction to the right and increasing H+
92
What is a sign of a Sertoli cell tumor in a man?
Excess estradiol in the blood
93
In the systemic circulation, what blood vessels have the largest pressure drop? Smallest pressure drop?
Arterioles have the largest drop, whereas the vena cava has the smallest pressure drop in systemic circulation.
94
What is the major stimulus for cell division in chondroblast?
IGF-1
95
What are two causes of diffusion impairment in the lungs?
Decrease in surface area and increase in membrane thickness (PalvO2 > PaO2)
96
What are the four effects of sucking on the mother?
1. Increased synthesis and secretion of oxytocin
2. Increased release of PIF by the hypothalamus
3. Inhibition of GnRH (suppressing FSH/LH)
4. Milk secretion
97
A migrating myoelectric complex is a propulsive movement of undigested material from the stomach to the small intestine to the colon. During a fast, what is the time interval of its repeats?
It repeats every 90 to 120 minutes and correlates with elevated levels of motilin.
98
With an increase in arterial systolic pressure, what happens to
Stroke volume?
Increases
99
Vessel compliance?
Decreases
100
Heart rate?
Decreases
101
What enzyme is needed to activate the following reactions?
| Trypsinogen to trypsin
Enterokinase
102
Chymotrypsinogen to chymotrypsin
Trypsin
103
Procarboxypeptidase to carboxypeptidase
Trypsin
104
In a ventricular pacemaker cell, what phase of the action potential is affected by ACh?
Phase 4; ACh hyperpolarizes the cell via increasing potassium conductance, taking longer to reach threshold and showing the rate of firing.
105
What is the most potent stimulus for glucagon secretion? Inhibition?
Hypoglycemia for secretion and hyperglycemia for inhibition
106
What is the term for the summation of mechanical stimuli due to the skeletal muscle contractile unit becoming saturated with calcium?
Tetany
107
What form of renal tubular reabsorption is characterized by low back leaks, high affinity of a substance, and easy saturation? It is surmised that the entire filtered load is reabsorbed until the carriers are saturated, and then the rest is excreted.
A transport maximum (Tm) system
108
In an adrenergic nerve terminal, where is dopamine converted to NE? By what enzyme?
Dopamine is converted into NE in the vesicle via the enzyme dopamine-β-hydroxylase.
109
Is the clearance for a substance greater than or less than for inulin if it is freely filtered and secreted? If it is freely filtered and reabsorbed?
Filtered and secreted: Cx > Cin (i.e., PAH). Filtered and reabsorbed: Cx < Cin (i.e., glucose), where Cx = clearance of a substance and Cin = clearance of inulin.
110
What is the term for the load on a muscle in the relaxed state?
Preload. It is the load on a muscle Prior to contraction.
111
The surge of what hormone is induces ovulation?
LH
112
What are the two best indices of left ventricular preload?
LVEDV and LVEDP (left ventricular end-diastolic volume and end-diastolic pressure, respectively)
113
What stage of male development is characterized by the following LH and testosterone levels?
LH pulsatile amplitude and levels increase, with increased testosterone production.
Puberty
114
Both LH and testosterone levels drop and remain low.
Childhood
115
LH secretion drives testosterone production, with both levels paralleling each other.
Adulthood
116
Decreased testosterone production is accompanied by an increase in LH production.
Aged adult
117
Why is the clearnace of creatinine always slightly greater than the clearance of inulin and GFR?
Because creatinine is filtered and a small amount is secreted
118
What primary acid-base disturbance is caused by a loss in fixed acid forcing the reaction to shift to the right, thereby increasing HCO3- levels?
Metabolic alkalosis (summary: high pH, low H+ and high HCO3-)
119
What referring to a series circuit, what happens to resistance when a resistor is added?
Resistance increases as resistors are added to the circuit.
120
Why is there an increase in prolactin if the hypothalamic-pituitary axis was severed?
Because the chronic inhibition of dopamine (PIF) on the release of prolactin from the anterior pituitary gland is removed, thereby increasing the secretion of prolactin.
121
What acid form of H+ in the urine cannot be titrated?
NH4+ (ammonium)
122
Regarding the venous system, what happens to blood volume if there is a small change in pressure?
Because the venous system is more compliant than the arterial vessels, small changes in pressure result in large changes in blood volume.
123
In what stage of sleep is GH secreted?
Stage 3 and 4 (NREM)
124
Where does the conversion of CO2 into HCO3- take place?
In the RBC; remember, you need carbonic anhydrase for the conversion, and plasma does not have this enzyme.
125
From the fourth month of fetal life to term, what secretes the progesterone and estrogen to maintains the uterus?
The placenta
126
What two factors are required for effective exocytosis?
Calcium and ATP are required for packaged macromolecules to be extruded from the cell.
127
What is the best measure of total body vitamin D if you suspect a deficiency?
Serum 25-hydroxy-vitamin D (25-OH-D)
128
What hormone is required for 1,25-dihydroxy-vitamin D (1,25-diOH-D) to have bone resorbing effects?
PTH
129
Is bone deposition or resorption due to increased interstitial Ca2+ concentrations?
Bone deposition increases with increased Ca2+ or PO4- concentrations, whereas resorption (breakdown) is increased when there are low levels of Ca2+ or PO4-.
130
The opening of what valve indicates the termination of isovolumetric relaxation phase of the cardiac cycle?
Opening of the mitral valve indicates the termination of the isovolumetric relaxation phase and the beginning of the ventricular filling phase.
131
Why is there a decrease in the production in epinephrine when the anterior pituitary gland is removed?
The enzyme phenyl ethanolamine N-methylatransferase (PNMT), used in the conversion of epinephrine, is regulated by cortisol. Removing the anterior pituitary gland decreases ACTH and therefore cortisol.
132
Name the period described by the following statement: no matter how strong a stimulus is, no further action potentials can be stimulated.
Absolute refractory period is due to voltage inactivation of sodium channels.
133
How many carbons do estrogens have?
Estrogens are 18-carbon steroids. (Removal of one carbon from an androgen produces an estrogen.)
134
True or false? The alveolar PO2 and PCO2 levels match the pulmonary end capillary blood levels.
True. Because of intrapulmonary shunting, there is a slight decrease in PO2 and increase in PCO2 between the pulmonary end capillary blood and the systemic arterial blood.
135
In high altitudes, what is the main drive for ventilation?
The main drive shifts from central chemoreceptors (CSF H+) to peripheral chemoreceptors monitoring low PO2 levels.
136
Describing what type of fluid is either gained or lost with the following changes in body hydration for the ECF volume, ICF volume, and body osmolarity, respectively:
ECF, decrease; ICF, no change; body, no change
Loss of isotonic fluid (diarrhea, vomiting, hemorrhage)
137
ECF, increase; ICF, increase; body, decrease
Gain of hypotonic fluid (water intoxication or hypotonic saline)
138
ECF, decrease; ICF, decrease; body, increase
Loss of hypotonic fluid (alcohol, diabetes insipidus, dehydration)
139
ECF, increase; ICF, no change; body, no change
Gain of isotonic fluid (isotonic saline)
140
ECF, increase; ICF, decrease; body, increase
Gain of hypertonic fluid (mannitol or hypertonic saline)
141
What hormone excess produces adrenal hyperplasia?
ACTH
142
Is there more circulating T3 or T4 in plasma?
T4; because of greater affinity for the binding protein, T4 has a significantly (nearly fifty times) longer half-life than T3.
143
Why is the cell's resting membrane potential negative?
The resting membrane potential of the cell is -90mV because of the intracellular proteins.
144
True or false? Thyroid size is a measure of its function.
False. Thyroid size is a measure of TSH levels (which are giotrogenic).
145
If the radius of a vessel is decreased by half, what happens to the resistance?
The resistance increases 16-fold.
146
What neurotransmitter is essential for maintaining a normal BP when an individual is standing?
NE, via its vasoconstriction action on blood vessels
147
What form of diabetes insipidus is due to an insufficient amount of ADH for the renal collecting ducts?
Central/neurogenic diabetes insipidus; in the nephrogenic form there is sufficient ADH available, but the renal collecting ducts are impermeable to its actions.
148
Name the three methods of vasodilation via the sympathetic nervous system.
1. Decrease α1 activity
2. Increase β2 activity
3. Increase ACh levels
149
What hormone is characterized by the following renal effects?
Calcium reabsorption, phosphate excretion
PTH
150
Calcium excretion, phosphate excretion
Calcitriol
151
Calcium reabsorption, phosphate reabsorption
Vitamin D3
152
True or false? Progesterone has thermogenic activities.
True. Elevated plasma levels of progesterone can raise the body temperature 0.5° to 1.0°F.
153
How long is the transit time through the small intestine?
2 to 4 hours
154
Where is the last conducting zone of lungs?
Terminal bronchioles. (No gas exchange occurs here.)
155
True or false? Cortisol inhibits glucose uptake in skeletal muscle.
True; cortisol inhibits glucose uptake in most tissue, making it available for neural tissue use.
156
What percentage of cardiac output flows through the pulmonary circuit?
100%; the percentage of blood flow through the pulmonary and systemic circulations are equal.
157
Name the Hgb-O2 binding site based on the following information:
Least affinity for O2; requires the highest PO2 levels for attachment (approx. 100 mmHg)
Site 4
158
Greatest affinity of the three remaining sites for attachment; requires PO2 levels of 26 mmHg to remain attached
Site 2
159
Remains attached under most physiologic conditions
Site 1
160
Requires a PO2 level of 40 mmHg to remain attached
Site 3
161
Which three factors cause the release of epinephrine from the adrenal medulla?
1. Exercise
2. Emergencies (stress)
3. Exposure to cold
(The three Es)
162
How many ATPs are hydrolyzed every time a skeletal muscle cross-bridge completes a single cycle?
One, and it provides the energy for mechanical contraction.
163
Why would a puncture to a vein above the heart have the potential to introduce air into the vascular system?
Venous pressure above the heart is subatmospheric, so a puncture there has the potential to introduce air into the system.
164
What type of saliva is produced under parasympathetic stimulation?
High volume, watery solution; sympathetic stimulation results in thick, mucoid saliva.
165
In what area of the GI tract does iron get absorbed?
Duodenum
166
Why is the apex of the lung hypoventilated when a person is standing upright?
The alveoli at the apex are almost completely inflated prior to inflation, and although they are large, they receive low levels of alveolar ventilation.
167
What pancreatic islet cell secrets glucagons?
α-Cells; glucagon has stimulatory effects on β-cells and inhibitory effects on δ-cells.
168
What are the four characteristics of all protein-mediated transportation?
1. Competition for carrier with similar chemical substances
2. Chemical specificity needed for transportation
3. Zero-order saturation kinetics (Tranportation is maximal when all transporters are saturated.)
4. Rate of transportation faster than if by simple diffusion
169
What is secretin's pancreatic action?
Secretin stimulates the pancreas to secrete a HCO3- rich solution to neutralize the acidity of the chyme entering the duodeum.
170
Why is there an increase in FF if the GFR is decreased under sympathetic stimulation?
Because RPF is markedly decreased, while GFR is only minimally diminished; this results in an increase in FF (remember FF = GFR/RPF).
171
What triggers phase 3 of the action potential in a ventricular pacemaker cell?
Rapid efflux of potassium
172
What is the primary target for the action of glucagon?
Liver (hepatocytes)
173
What is the renal compensation mechanism for acidosis?
Production of HCO3-, shifting the reaction to the left and thereby decreasing H+
174
What enzyme found in a cholinergic synapse breaks down ACh? What are the byproducts?
Acetylcholinesterase breaks ACh into acetate and choline (which gets resorbed by the presynaptic nerve terminal).
175
What hormone, produced by Sertoli cells, if absent would result in the formation of internal female structures?
MIF
176
What happens to the lung if the intrapleural pressure exceeds lung recoil?
The lung will expand; also the opposite is true.
177
What two factors determine the clearance of a substance?
Plasma concentration and excretion rate
178
What type of muscle contraction occurs when the muscle shortens and lifts the load placed on it?
Isotonic contraction
179
What type of potential is characterized as being an all-or-none response, propagated and not summated?
Action potential
180
What primary acid-base disturbance is caused by a gain in fixed acid forcing the reaction to shift to the left, decreasing HCO3- and slightly increasing CO2?
Metabolic acidosis (summary: low pH, high H+, and low HCO3-)
181
What two pituitary hormones are produced by acidophils?
GH and prolactin are produced by acidophils; all others are by basophils.
182
What organ of the body has the smallest AV oxygen difference?
The renal circulation has the smallest AV O2 (high venous PO2) difference in the body because of the overperfusion of the kidneys resulting from filtration.
183
What is the titratable acid form of H+ in the urine?
H2PO4- (dihydrogen phosphate)
184
What hypothalamic hormone is synthesized in the preoptic nucleus?
GnRH
185
What five factors promote turbulent flow?
1. Increased tube radius
2. Increased velocity
3. Decreased viscosity
4. Increased number of branches
5. Narrowing of an orifice
186
What is the major hormone produced in the following areas of the adrenal cortex?
Zona glomerulosa
Aldosterone
187
Zona fasciculata
Cortisol
188
Zona reticularis
DHEA (androgens)
| Remember, from the outer cortex to the inner layer, Salt, Sugar, Sex. The adrenal cortex gets sweeter as you go deeper.
189
Where is most of the body's Ca2+ stored?
In bone; nearly 99% of Ca2+ is stored in the bone as hydroxyapatite.
190
What is the relationship between ventilation and PCO2 levels?
They are inversely related. If ventilation increases, there will be a decrease in PCO2 levels and vice versa.
191
Is T3 or T4 responsible for the negative feedback loop on to the hypothalamus and anterior pituitary gland?
T4, as long as T4 levels remain constant, TSH will be minimally effected by T3.
192
What is the signal to open the voltage-gated transmembrane potassium channels?
Membrane depolarization is the stimulus to open these slow channels, and if they are prevented from opening, it will slow down the repolarization phase.
193
Increased urinary excretion of what substance is used to detect excess bone demineralization?
Hydroxyproline
194
What is the term to describe how easily a vessel stretches?
Compliance (think of it as distensibility)
195
What is the ratio of T4:T3 secretion from the thyroid gland?
20:1 T4:T3. There is an increase in the production of T3 when iodine becomes deficient.
196
Do the PO2 peripheral chemoreceptors of the carotid body contribute to the normal drive for ventilation?
Under normal resting conditions NO, but they are strongly stimulated when PO2 arterial levels decrease to 50 to 60 mmHg, resulting in increased ventilatory drive.
197
What determines the overall force generated by the ventricular muscle during systole?
The number of cross-bridges cycling during contraction: the greater the number, the greater the force of contraction.
198
Where does most circulating plasma epinephrine originate?
From the adrenal medulla; NE is mainly derived from the postsynaptic sympathetic neurons.
199
What causes a skeletal muscle contraction to terminate?
When calcium is removed from troponin and pumped back into the SR, skeletal muscle contraction stops.
200
What happens to intracellular volume when there is an increase in osmolarity?
ICF volume decreases when there is an increase in osmolarity and vice versa.
201
Which CHO is independently absorbed from the small intestine?
Fructose; both glucose and galactose are actively absorbed via secondary active transport.
202
When is the surface tension the greatest in the respiratory cycle?
Surface tension, the force to collapse the lung, is greatest at the end of inspiration.
203
What adrenal enzyme deficiency results in hypertension, hypernatremia, increased ECF volume, and decreased adrenal androgen production?
17-α-Hydroxylase deficiency
204
In reference to membrane potential (Em) and equilibrium potential (Ex), which way do ions diffuse?
Ions diffuse in the direction to bring the membrane potential toward the equilibrium potential.
205
Under normal conditions, what is the main factor that determines GFR?
Hydrostatic pressure of the glomerular capillaries (promotes filtration)
206
The closure of what valve indicates the beginning of the isovolumetric relaxation phase of the cardiac cycle?
Closure of the aortic valve indicates the termination of the ejection phase and the beginning of the isovolumetric relaxation phase of the cardiac cycle.
207
What vessels in the systemic circulation have the greatest and slowest velocity?
The aorta has the greatest velocity and the capillaries have the slowest velocity.
208
Thin extremities, fat collection on the upper back and abdomen, hypertension, hypokalemic alkalosis, acne, hirsutism, wide purple striae, osteoporosis, hyperlipidemia, hyperglycemia with insulin resistance, and protein depletion are all characteristics of what disorder?
Hypercortisolism (Cushing syndrome)
209
What enzyme is essential for the conversion of CO2 to HCO3-?
Carbonic anhydrase
210
True or false? The parasympathetic nervous system has very little effect on arteriolar dilation or constriction.
True
211
What three lung measurements must be calculated because they cannot be measured by simple spirometry?
TLC, FRC, and RV have to be calculated. (Remember, any volume that has RV as a component has be calculated.)
212
What is the venous and arterial stretch receptors' function regarding the secretion of ADH?
They chronically inhibit ADH secretion; when there is a decrease in the blood volume, the stretch receptors send fewer signals, and ADH is secreted.
213
What cell converts androgens to estrogens?
Granulosa cell
214
What hormone acts on Granulosa cell?
FSH
215
How long is the transit time through the large intestine?
3 to 4 days
216
Does subatmospheric pressure act to expand or collapse the lung?
Subatmospheric pressure acts to expand the lung; positive pressure acts to collapse the lung.
217
What hormone constricts afferent and efferent arterioles (efferent more so) in an effort to preserve glomerular capillary pressure as the renal blood flow decreases?
AT II
218
Why is there a minimal change in BP during exercise if there is a large drop in TPR?
Because the large drop in TPR is accompanied by a large increase in cardiac output, resulting in a minimal change in BP.
219
What is the effect of insulin on protein storage?
Insulin increases total body stores of protein, fat, and CHOs. When you think insulin, you think storage.
220
What is the term for an inhibitory interneuron?
Renshaw neuron
221
What triggers phase 0 of the action potential in a ventricular pacemaker cell?
Calcium influx secondary to slow channel opening
222
What are the following changes seen in the luminal fluid by the time it leaves the PCT of the nephron?
Percentage of original filtered volume left in the lumen
At the end of the PCT 25% of the original volume is left
223
Percentage of Na+, Cl-, K+ left in the lumen
At the end of the PCT 25% of Na+, Cl-, K+ is left
224
Osmolarity
300 mOsm/L
225
Concentration of CHO, AA, ketons, peptides
No CHO, AA, ketons, or peptide are left in the tubular lumen.
226
True or false? Enterokinase is a brush border enzyme.
False. It is an enzyme secreted by the lining of the small intestine.
227
Where does the synthesis of ACh occur?
In the cytoplasm of the presynaptic nerve terminal; it is catalyzed by choline acetyltransferase.
228
What pancreatic islet cell secrets somatostatin?
δ-Cells; somatostatin has an inhibitory effect on α- and β-islet cells.
229
Why is O2 content depressed in anemic patients?
Anemic patients have a depressed O2 content because of the reduced concentration of Hgb in the blood. As for polycythemic patients, their O2 content is increased because of the excess Hgb concentrations.
230
What term describes the volume of plasma from which a substance is removed over time?
Clearance
231
If capillary hydrostatic pressure is greater than oncotic pressure, is filtration or reabsorption promoted?
Filtration; if hydrostatic pressure is less than oncotic pressure, reabsorption is promoted.
232
What cells of the parathyroid gland are simulated in response to hypocalcemia?
The chief cells of the parathyroid gland release PTH in response to hypocalcemia.
233
At the base of the lung, what is the baseline intrapleural pressure, and what force does it exert on the alveoli?
Intrapleural pressure at the base is -2.5 cm H2O (more positive than the mean), resulting in a force to collapse the alveoli.
234
What hormone is necessary for normal GH secretion?
Normal thyroid hormones levels in the plasma are necessary for proper secretion of GH. Hypothyroid patients have decreased GH secretions.
235
What is the signal to open the voltage-gated transmembrane sodium channels?
Membrane depolarization is the stimulus to open these channels, which are closed in resting conditions.
236
What hormones are produced in the median eminence region of the hypothalamus and the posterior pituitary gland?
None; they are the storage sites for ADH and oxytocin.
237
What is the most energy-demanding phase of the cardiac cycle?
Isovolumetric contraction
238
What presynaptic receptor does NE use to terminate further neurotransmitter release?
α2-Receptors
239
Are salivary secretions hypertonic, hypotonic, or isotonic?
Hypotonic, because NaCl is reabsorbed in the salivary ducts
240
What is the effect of T3 on heart rate and cardiac output?
T3 increases both heart rate and cardiac output by increasing the number of β-receptors and their sensitivity to catecholamines.
241
Why will turbulence first appear in the aorta in patients with anemia?
Because it is the largest vessel and has the highest velocity in systemic circulation
242
What is the origin of the polyuria if a patient is dehydrated and electrolyte depleted?
If the polyuria begins before the collecting ducts, the patient is dehydrated and electrolyte depleted. If the polyuria originates from the collecting ducts, the patient is dehydrated with normal electrolytes.
243
What is the physiologically active form of Ca2+?
Free ionized Ca2+
244
What are the two factors that affect alveolar PCO2 levels?
Metabolic rate and alveolar ventilation (main factor)
245
Why is spermatogenesis decreased with anabolic steroid therapy?
Exogenous steroids suppress LH release and result in Leydig cell atrophy. Testosterone, produced by Leydig cells, is needed for spermatogenesis.
246
What type of membrane is characterized as being permeable to water only?
Semipermeable membrane; a selectively permeable membrane allows both water and small solutes to pass through its membrane.
247
What thyroid enzyme is needed for oxidation of I- to I'?
Peroxidase, which is also needed for iodination and coupling inside the follicular cell
248
What is the most important stimulus for the secretion of insulin?
An increase in serum glucose levels
249
What term is described as the prestretch on the ventricular muscle at the end of diastole?
Preload (the load on the muscle in the relaxed state)
250
What peripheral chemoreceptor receives the most blood per gram of weight in the body?
The carotid body, which monitors arterial blood directly
251
What adrenal enzyme deficiency results in hypertension, hypernatremia, and virilization?
11-β-Hydroxylase deficiency results in excess production of 11-deoxycorticosterone, a weak mineralcorticoid. It increases BP, Na=, and ECF volume along with production of adrenal androgens.
252
What is the term for diffusion of water across a semipermeable or selectively permeable membrane?
Osmosis; water will diffuse from higher to lower water concentrations.
253
When do hCG concentrations peak in pregnancy?
In the first 3 months
254
How many milliliters of O2 per mililiter of blood?
0.2
255
What type of cell is surrounded by mineralized bone?
Osteocyte
256
What two forces affect movement of ions across a membrane?
Concentration force and electrical force
257
What happens to the resistance of the system when a resistor is added in a series?
Resistance of the system increases. (Remember, when resistors are connected in a series, the total of the resistance is the sum of the individual resistances.)
258
What is the greatest component of lung recoil?
Surface tension; in the alveoli, it is a force that acts to collapse the lung.
259
Where is ADH synthesized?
In the supraoptic nuclei of the hypothalamus; it is stored in the posterior pituitary gland.
260
How is velocity related to the total cross-sectional area of a blood vessel?
Velocity is inversely related to cross-sectional area.
261
True or false? Aldosterone has a sodium-conserving action in the distal colon.
True. In the distal colon, sweat glands, and salivary ducts, aldosterone has sodium-conserving effects.
262
What form of hormone is described as having membrane-bound receptors that are stored in vesicles, using second messengers, and having its activity determined by free hormone levels.
Water-soluble hormones are considered fast-acting hormones.
263
What forms of fatty acids are absorbed from the small intestine mucosa by simple diffusion?
Short-chain fatty acids
264
What is the term for the day after the LH surge in the female cycle?
Ovulation
265
The opening of what valve indicates the beginning of the ejection phase of the cardiac cycle?
Opening of the aortic valve terminates the isovolumetric phase and begins the ejection phase of the cardiac cycle.
266
What is the region of an axon where no myelin is found?
Nodes of Ranvier
267
What disorder of aldosterone secretion is characterized by
Increased total body sodium, ECF volume, plasma volume, BP, and pH; decreased potassium, renin and AT II activity; no edema?
Primary hyperaldosteronism (Conn syndrome)
268
Decreased total body sodium, ECF volume, plasma volume, BP, and pH; increased potassium, renin, and AT II activity; no edema?
Primary hypoaldosteronism (Addison's disease)
269
What four factors affect diffusion rate?
1. Concentration (greater concentration gradient, greater diffusion rate)
2. Surface area (greater surface area, greater diffusion rate)
3. Solubility (greater solubility, greater diffusion rate)
4. Membrane thickness (thicker the membrane, slower the diffusion rate)
Molecular weight is clinically unimportant.
270
How long after ovulation does fertilization occur?
8 to 25 hours
271
What is the name of the force that develops in the wall of the lungs as they expand?
Lung recoil, being a force to collapse the lung, increases as the lung enlarges during inspiration.
272
What day of the menstrual cycle does ovulation take place?
Day 14
273
How does sympathetic stimulation to the skin result in decreased blood flow and decreased blood volume? (Hint: what vessels are stimulated, and how?)
A decrease in cutaneous blood flow results from constriction of the arterioles, and decreased cutaneous blood volume results from constriction of the venous plexus.
274
What two compensatory mechanisms occur to reverse hypoxia at high altitudes?
Increase in erythropoietin and increase in 2,3-BPG, also called 2,3-diphosphoglycerate (2,3,-P2Gri) (increase in glycolysis)
275
What female follicular cell is under LH stimulation and produces androgens from cholesterol?
Theca cell
276
What is the main factor determing FF?
Renal plasma flow (decrease flow, increase FF)
277
Where is the action potential generated on a neuron?
Axon hillock
278
If free water clearance (CH2O) is positive, what type of urine is formed? And if is negative?
If positive, hypotonic urine (osmolarity < 300 mOsm/L); if negative, hypertonic urine (osmolarity > 300 mOsm/L)
279
What cell in the heart has the highest rate of automaticity?
SA node; it is the reason it is the primary pacemaker of the heart.
280
What is pumped from the lumen of the ascending loop of Henle to decrease the osmolarity?
NaCl is removed from the lumen to dilute the fluid leaving the loop of Henle.
281
True or false? In skeletal muscle relaxation is an active event.
True. Sarcoplasmic calcium-dependent ATPase supplies the energy to terminate contraction, and therefore it is an active process.
282
What three factors increase simple diffusion?
1. Increased solubility
2. Increased concentration gradient
3. Decreased thickness of the membrane
283
What is the pancreatic action of CCK?
CCK stimulates the pancreas to release amylase, lipase, and proteases for digestion.
284
What is the rate-limiting step in a conduction of a NMJ?
The time it takes ACh to diffuse to the postjunctional membrane
285
Is excretion greater than or less than filtration for net secretion to occur?
Excretion is greater than filtration for net secretion to occur.
286
What acid-base disturbance is produced from vomiting?
Hypokalemic metabolic alkalosis occurs from vomiting because of the loss of H+, K+, and Cl-.
287
What phase of the menstrual cycle is dominated by estrogen? Progesterone?
Follicular phase is estrogen-dependent with increased FSH levels, while the luteal phase is progesterone-dependent.
288
Name the lung measurement based on the following descriptions:
The amount of air that enters or leaves the lung system in a single breath
Tidal volume (VT)
289
The maximal volume inspired from FRC
Inspiratory capacity
290
Additional volume that can be expired after normal expiration
ERV
291
Maximal volume that can be expired after maximal inspiration
VC
292
Volume in the lungs at the end of passive expiration
FRC
293
Additional air that can be taken in after normal inspiration
IRV
294
Amount of air in the lungs after maximal expiration
RV
295
Amount of air in the lungs after maximal inspiration
TLC
296
What growth factors are chondrogenic, working on the epiphyseal end plates of bone?
Somatomedins (IGF-1)
297
What determines the Vmax of skeletal muscle?
The muscle's ATPase activity
298
True or false? All of the hormones in the hypothalamus and anterior pituitary gland are water soluble.
True.
299
What is the effect of T3 on the glucose absorption in the small intestine?
Thyroid hormones increase serum glucose levels by increasing the absorption of glucose from the small intestine.
300
Is the bound form or free form of a lipid-soluble hormone responsible for the negative feedback activity?
Free form determines hormone activity and is responsible for the negative feedback loop.
301
What region or regions of the adrenal cortex are stimulated by ACTH?
Zona fasciculata and zona reticularis
302
Are the following parameters associated with an obstructive or restrictive lung disorder; decreased FEV1, FVC, peak flow, and FEV1/FVC; increased TLC, FRC, and RV?
Obstructive lung disorders. The opposite changes (where you see decrease exchange it for increase and vice versa) are seen in a restrictive pattern.
303
What is the respiratory compensation mechanism for metabolic alkalosis?
Hypoventilation, which increases CO2, shifting the reaction to the right and increasing H+
304
During puberty, what is the main drive for the increased GH secretion?
Increased androgen secretion at puberty drives the increased GH secretion.
305
What type of potential is characterized as graded, decremental, and exhibiting summation?
Subthreshold potential
306
What three organs are responsible for peripheral conversion of T4 to T3?
Liver, kidneys, and pituitary gland via 5' deiodinase enzyme
307
The closure of what valve indicates the beginning of isovolumetric contraction?
Mitral valve closure indicates the termination of the ventricular filling phase and beginning of isovolumetric contraction.
308
How many carbons do androgens have?
Androgens are 19-carbon steroids.
309
At the apex of the lung, what is the baseline intrapleural pressure, and what force does it exert on the alveoli?
Baseline apical intrapleural pressure is -10 cmH2o (more negative than the mean) resulting in a force to expand the alveoli.
310
True or false? Renin secretion is increased in 21-β-hydroxylase deficiency.
True. Increased renin and AT II levels occur as a result of the decreased production of aldosterone.
311
What are the four ways to increase TPR?
1. Decrease the radius of the vessel
2. Increase the length of the vessel
3. Increase the viscosity
4. Decrease the number of parallel channels
312
What form of estrogen is of placental origin?
Estriol
313
What term is an index of the effort needed to expand the lungs (i.e., overcomes recoil)?
Compliance; the more compliant a lung is, the easier it is to inflate.
314
At which three sites in the body is T4 converted to T3?
1. Liver
2. Kidney
3. Pituitary gland (via 5'-deiodinase enzyme)
315
Using Laplace's relationship regarding wall tension, why is the wall tension in a aneurysm greater than in the surrounding normal blood vessel's wall?
The wall tension is greater because the aneurysm has a greater radius than the surrounding vessel.
316
What percentage of nephrons is cortical?
Seven-eighths of nephrons are cortical, with the remainder juxtamedullary.
317
To what is the diffusion rate indirectly proportional?
Diffusion rate is indirectly proportional to membrane thickness and is directly proportional to membranes surface area.
318
ADH is secreted in response to what two stimuli?
ADH is secreted in response to increased plasma osmolarity and decreased blood volume.
319
What vessels have the largest total cross-sectional area in systemic circulation?
Capillaries
320
How many days before the first day of menstrual bleeding is ovulation?
14 days in most women (Remember, the luteal phase is always constant.)
321
What is the major muscle used in the relaxed state of expiration?
Under resting conditions expiration is considered a passive process; therefore, no muscles are used. In the active state the abdominal muscles can be considered the major muscle of expiration.
322
What subunit of hCG is used to detect whether a patient is pregnant?
The β-subunit; remember, the α-subunit is nonspecific.
323
What happens to capillary oncotic pressure with dehydration?
Oncotic pressure increases because of the removal of water.
324
What cells of the kidney are extravascular chemoreceptors for decreased Na+, Cl-, and NaCl?
Macula densa
325
What is the effect of insulin on intracellular K+ stores?
Insulin increases intracellular K+ stores while decreasing serum K+ levels.
326
What triggers phase 4 of the action potential in a ventricular pacemaker cell?
Decreasing potassium conductance, which results in increased excitability.
327
What is it called when levels of sex steroids increase, LH increases, and FSH increases?
GnRH pulsatile infusion
328
What parasympathetic neurotransmitter of the GI tract stimulates the release of gastrin?
Gastrin-releasing peptide (GRP) stimulates G cells to release gastrin. (All G's)
329
What reflex increases TPR in an attempt to maintain BP during a hemorrhage?
The carotid sinus reflex
330
What is the name of the regulatory protein that covers the attachment site on actin in resting skeletal muscle?
Tropomyosin
331
Which way does the Hgb-O2 dissociation curve shift in patients with CO poisoning?
The pathologic problem with CO poisoning is that CO has 240 times as much affinity for Hgb molecule as does O2, reducing the carrying capacity and shifting the curve to the left, making it difficult to remove the CO molecule from Hgb.
332
What is the main factor determining GFR?
Glomerular capillary pressure (increased glomerular capillary pressure, increased GFR and vice versa)
333
What is the effect of hypoventilation on cerebral blood flow?
Hypoventilation results in an increase in PCO2 levels and therefore an increase in blood flow.
334
What cells of the thyroid gland are stimulated in response to hypercalcemia?
The parafollicular cells of the thyroid (C cells) release calcitonin in response to hypercalcemia.
335
What is the term for the amount of blood in the ventricle after maximal contraction?
Residual volume
336
What does failure of PaO2 to increase with supplemental O2 indicate?
Pulmonary shunt (i.e., pulmonary embolism)
337
What two substances stimulate Sertoli cells?
FSH and testosterone
338
The clearance of what substance is the gold standard of RPF?
PAH
339
What bile pigment is formed by the metabolism of bilirubin by intestinal bacteria, giving stool its brown color?
Stercobilin
340
Is ACh associated with bronchoconstriction or bronchodilation?
Bronchoconstriction is associated with parasympathetic stimulation (ACh), and catecholamine stimulation is associated with bronchodilation (why epinephrine is used in emergency treatment of bronchial asthma.)
341
What are the growth factors released from the liver called?
Somatomedins
342
Regarding skeletal muscle mechanics, what is the relationship between velocity and afterload?
An increase in the afterload decreases velocity; they are inversely related. (V equals 1 divided by afterload.)
343
What happens to extracellular volume with a net gain in body fluid?
The ECF compartment always enlarges when there is a net gain in total body water and decreases when there is a loss of total body water. Hydration status is named in terms of the ECF compartment.
344
What are the six substances that promote the secretion of insulin?
1. Glucose
2. Amino acid (arginine)
3. Gastrin inhibitory peptide (GIP)
4. Glucagon
5. β-Agonists
6. ACh
345
Does O2 or CO2 have a higher driving force across the alveolar membrane?
O2 has a higher driving force but is only one-twenty-fourth as soluble as CO2. CO2 has a very small partial pressure difference across the alveolar membrane (47 - 40 = 7 mmHg), but it is extremely soluble and therefore diffuses readily across the membrane.
346
What is used as an index for both adrenal and testicular androgens?
Urinary 17-ketosteroids
347
How are resistance and length related regarding flow?
Resistance and vessel length are proportionally related. The greater the length of the vessel, the greater the resistance is on the vessel.
348
Is filtration greater than or less than excretion for net reabsorption to occur?
Filtration is greater than excretion for net reabsorption to occur.
349
What hormone, stimulated by epinephrine, results in an increase in lipolysis?
Hormone-sensitive lipase, which breaks down triglyceride into glycerol and free fatty acid
350
True or false? Miniature end-plate potentials (MEPPs) generate action potentials.
False
351
Is GH considered a gluconeogenic hormone?
Yes, it decreases fat and muscle uptake of glucose, thereby increasing blood glucose levels.
352
True or false? Somatic motor neutrons innervate the striated muscle of the bulbospongiosus and ischiocavernous muscles and result in ejaculation of semen.
True
353
What happens to intraventricular pressure and volume during isovolumetric contraction?
As the name indicates, there is no change in volume but there is an increase in pressure.
354
Do high levels of estrogen and progesterone block milk synthesis?
Yes, they stimulate the growth of mammary tissue but block milk synthesis. At parturition, the decrease in estrogen lifts the block on milk production.
355
What two factors lead to the development of the bends (caisson disease)?
Breathing high-pressure nitrogen over a long time and sudden decompression result in the bends.
356
In what type of circuit is the total resistance always less than that of the individuals resistors?
Parallel circuit
357
What is the term for days 15 to 28 in the female cycle?
Luteal phase
