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Which of the following coenzymes is NOT used by pyruvate dehydrogenase?
c) thiamine pyrophosphate
e) lipoic acid
Describe the three layers of the wall of a blood vessel. How do they differ between arteries, veins, and capillaries? Which vessels have valves and why?
*Capilllaries are only a single layer of simple squamous epithelium
--Arteries have more tunica mediaàmore elastic and better control over diameter
---Veins have thinner tunica mediaàcollapse when empty, less control over diameter
What is a portal system? What is the usefulness of these systems?
Bands of smooth muscle that can alter blood flow through the capillary beds. When sphincters are relaxed, blood flows through all the capillaries in the bed, but upon constricting, blood flow bypasses capillaries completely and flows through metarterioles.
What is a metarteriole and what does it do?
A branch of arterioles that is only partially surrounded by smooth muscles. Blood flowing through metarterioles can take one of two paths, depending on the contractile state of the precapillary sphincter.
What is the difference between fenestrated and unfenestrated capillaries?
What is angiogenesis? What stimulates it?
--Controlled by cytokines and stimulated by growth factors (mitogens—promote mitosis), such as VEGF, FGF, FSH
What factors affect blood flow?
Velocity of blood flow depends on total cross sectional area of blood vessels
What is the difference between laminar blood flow and turbulent blood flow? What might cause the latter? How would a clinician be able to detect turbulent blood flow?
Normal blood flow is laminar and silent; narrowed arteries can cause turbulent blood flow (noisy)
What is peripheral vascular resistance? What factors affect PVR? Which have the greatest influence on PVR?
o Blood Viscosity (hematocrit)
o Total blood vessel length
o Blood vessel diameter (Has the greatest influence? Because resistance varies inversely with the fourth power of vessel radius)
How do changes in PVR affect BP?
Mean arterial pressure (MAP)= CO x resistance
*BP is highest in arteries and lowest in veins because energy is lost due to resistance to flow offered by the vessels.
What is Poiseuille’s Law?
Diastolic BP—heart is at rest; normal is less than 80
Systolic BP—heart is contracting; normal is less than 120
What is pulse pressure? What is mean arterial pressure & what factors affect it?
Be able to calculate both of these without a calculator.
Pulse pressure = systolic pressure - diastolic pressure
Mean arterial pressure (MAP) = diastolic pressure + 1/3(systolic pressure – diastolic pressure)
What is afterload and what produces it? How does it affect CO?
Afterload = EDV + Resistance in arterioles
o (How much work the heart has to do to move the blood)
o Reduce afterload = increased CO
What is HTN?
Hypertension—consistently elevated blood pressure; greater than 140/90 for repeated measurements
Thumping noise that is heard when blood squeezes through a compressed artery; used for taking blood pressure
How does the body regulate BP?
What are baroreceptors and where are they found?
---Located in carotid arteries and aorta
What substances act as metabolic vasodilators?
NO, epinephrine, adenosine, CO2
How does the sympathetic NS affect BP?
Norepinephrine (sympathetic stimulation)—regulates arteriole resistance
Increased norepinephrine = vasoconstriction
Through which type of blood vessels is blood flow the slowest and why?
Blood flow is slowest in the capillaries to allow time for exchange of gases and nutrients
What is bulk flow and what causes it?
Mass movement as a result of hydrostatic or osmotic pressure gradients
What is the difference between absorption and filtration? Where in capillaries does each of these occur?
--Net absorption at venous end
--Net filtration at arterial end
o Return fluid and proteins to circulatory system
o Picks up absorbed fat and transfers it to circulatory system
o Serves as a filter for pathogens
What is edema? What are some of its causes?
o Increase in hydrostatic pressure
o Decrease in plasma protein concentration
o Increase in interstitial proteins
· Caused by inadequate drainage of lymph
o Filtration >>> Absorption
What is the baroreceptor response to hypertension and hypotension?
What is CHF? What happens if there is right-sided failure (i.e., low CO from the right ventricle)? What happens if there is left-sided failure (i.e., low CO from the left ventricle)?
o Left sided failure—left side has to work harder to pump same amount of blood
o Right sided failure—usually occurs as a result of left-sided failure; when left side failure occurs, increased fluid pressure is transferred back through the lungs, it ultimately damages heart’s right side
What is the renin-angiotensin system, and how does it regulate BP?
1) Decreased sodium and effective circulatory volume stimulate juxtaglomerular cells to release renin.
2) Renin converts the inactive angiotensinogen (from liver) into angiotensin I, which is also inactive.
3)Angiotension-converting enzyme (ACE) converts angiotensin I to angiotensin II, which is active.
4) Angiotension II directly causes vasoconstriction, and therefore an increase in BP.
5) Angiotension also stimulates release of aldosterone from the adrenal gland. Aldosterone is a mineralocorticoid, meaning it regulates Na+ and K+ levels. (Acts on kidney to conserve Na+ if levels get too low)
6) Aldosterone conserves Na+
7) Aldosterone stimulates release of antidiuretic hormone (ADH) from posterior pituitary. ADH prevents the loss of fluid by the kidney and increases effective circulatory volume and therefore BP.
What is an ACE inhibitor and why is it used to treat hypertension?
What is aldosterone and what organ produces it? What stimulates its release and what does it do?
What is ANP and what organ produces it? What stimulates its release and what does it do?
What is ADH? What brain region produces it and from what organ it is released? What stimulates its release and what does it do?
What are the functions of the respiratory system?
What structures are involved in preparing inspired air to enter lower respiratory structures and what do they do?
--Air is filtered in trachea and bronchi
--Mucous traps inhaled particles
What is the difference between ventilation and respiration? Internal & external respiration?
o External Respiration—gas exchange between lungs and capillaries
o Internal Respiration—gas exchange between tissues and capillaries
What is the difference between the conducting zone and respiratory zone? What structures are associated with each?
o Upper respiratory tract (nasal cavity, pharynx, tongue, vocal chords, esophagus, larynx)
o Lower respiratory tract (trachea and lungs)
What muscles are involved in normal inspiration, normal expiration, forced inspiration, and forced expiration? What is the major muscle of breathing and what nerve innervates it? What division of the NS is this part of?
*Major muscle of breathing is the diaphragm and is innervated by the phrenic nerve (part of sympathetic NS)
What is the pleural membrane and what is its role in lung inflation? What happens if the pleural membrane is ruptured?
In what ways does the airway structure change as you go from the upper airway deeper into the lower airways? How do these changes relate to function and pathology?
o Decrease diameter
o Increase surface areaàless resistance at terminal bronchioles
o Slowly lose cartilage but gain smooth muscle (Functional significance?)
o Epithelia flattens out (Functional significance?)
What is the difference between a type I pneumocyte and a type II pneumocyte?
What prevents the movement of fluid from the capillaries into the tissues that surround the lungs?
How is pressure related to volume (Boyle’s Law)?
What is the partial pressure of a gas (Dalton’s Law)?
Partial pressure of a gas = atm. pressure x % of gas in atmosphere
Know what the following terms indicate and be able to identify them on a spirometry tracing: TV, IRV, ERV, VC, Residual volume.
What is minute volume?
Volume of gas inhaled/exhaled per minute
Intrapleural pressure is negative due to recoil of chest and lungs away from each other
What is compliance? What does it mean if the lungs have low compliance?
Compliance—ability to stretch; ∆volume∆work
o High compliance: lungs stretch easily
o Low compliance: requires more force to stretch
--Restrictive lung diseases
How are compliance, elasticity, and resistance related?
Surface tension created by the thin fluid layer between alveolar cells and the air creates most of the resistance to stretch.
What is surface tension? How does surfactant affect surface tension in the lungs? Why do smaller alveoli have more surfactant than larger ones? What happens to alveoli if there is a deficit in surfactant?
What changes in the upper airway affect resistance and airflow? What changes in the lower airway affect resistance and airflow? Why might these differ?
How does the ANS affect airway resistance?
Can contstrict/dilate bronchioles. Parasympathetic innervation can cause constriction whereas sympathetic (epi) can open up and relax bronchioles.
How does total alveolar ventilation differ from total pulmonary ventilation (minute volume)?
Why is ventilating the anatomic dead space considered a cost of ventilation?
The dead space is not fresh air to the alveoli, however it still is ventilated, which costs energy.
Know what the following terms mean: eupnea, hyperventilation, hypoventilation, dyspnea, apnea
How does hyperventilation affect PO2 and PCO2 in the alveoli? How does hypoventilation affect these?
What is ventilation-perfusion matching?
How does blood flow to the pulmonary arterioles change with changes in PO2 and PCO2? Is this the same or different from changes in the systemic circulation under the same oxygenation/CO2 status?
If PCO2 goes up, bronchioles dilate and so do systemic arteries. If PO2 goes up, bronchioles constrict and so do systemic arteries. It is basically opposite occurences for pulmonary and systemic arteries, as well as increases to decreases in PO2 or PCO2.
Know normal blood gas values (PCO2 and PO2) in the arterial and venous system as well as in the lungs (alveolar) and in the tissues.
What is hypoxia? What are some of the things that can result in hypoxia?
What are some of the ways that alveolar ventilation is altered and what causes them?
Decreased lung compliance, increased airway resistance, or drug overdoes that cause CNS depression.
How many molecules of oxygen can 1 molecule of hemoglobin carry?
4 binding sites (4 O2 molecules)
What is the difference between PO2 and oxygen saturation (SaO2)? How does a change in PO2 affect SaO2?
How does pH affect oxygen dissociation and what is the Bohr effect? How is this biologically relevant?
High H+ ion content = lower pH = lower binding (SaO2) of O2 (even if partial pressure doesn’t change)
What other substances (besides pH) affect oxygen binding to hemoglobin and how is this biologically relevant?
Know how increased CO2 affects pH and bicarb levels.
What is the chloride shift and where does this occur?
Occurs in RBC membrane. Cell trades 1 Cl- for 1 bicarb ion to either move it in or out of the cell (helps carbonic amylase do its job with converting CO2 and water to bicarb, or even reverse reaction)
How does the body detect changes in blood gases? How do these changes affect ventilation? Which has a greater effect on ventilation: change in O2 or change in CO2 levels? Why?
What CNS structures affect ventilation? Which affects inspiration and which affects expiration?
Why isn’t giving lots of O2 a good idea to someone with a chronic breathing disorder like COPD?
Their Hb becomes saturated with O2 instead of CO2 (which they struggle to get rid of anyway), so it builds up.
Bicarbonate is often given in code situations where the patient has had a prolonged period of cardiac and respiratory arrest. Why might this be the case?
Increasing the pH of the body can cause Hb to have higher affinity for O2 which is important for organs deprived of O2 for a long time.
What are the 4 layers of the wall of the GI tract and what major structures do they contain?
What are peristalsis and segmentation?
What are the components of saliva and what does it do?
What organ contains rugae and what is their purpose?
Inner layer of stomach and they increase SA and allow stretch of stomach
What is unique about the muscularis externa of the stomach and how does this relate to its function?
It has 3 layers (only place in GI tract with this) of muscles for better mechanical breakdown of food.
What do the parietal and chief cells of the gastric glands secrete and what is their function?
What do the mucous neck cells in gastric glands secrete and what is the purpose of this secretion?
What is the long reflex, what major nerve is involved in this, and how does it regulate gastric activity?
Comes from medulla oblongata. Body senses food (sight/smell/taste) and signal travels down preganglionic parasympathetic neuron in vagus nerve into enteric plexus. Then goes our postganglionic PS and intrinsic enteric neurons to effector cells (promote secretion/motility).
What is the short reflex and how does it regulate gastric activity?
Localized effect: acidic stomach pH triggers release of pepsinogen by chief cells to break down proteins. Works by distension or sensing peptides/amino acids in lumen of stomach. This sensory input travels to enteric plexus then to effector cells the same way long reflex does.
What types of stimuli activate the long reflex?
Sight; Smell; Taste; Thought of food initiate cephalic reflexes in medulla.
What is the postprandial alkaline tide and what causes it?
The bicarbonate in parietal cells leaves through capillaries – causes capillaries around stomach to be more basic than elsewhere.
What prevents the acidic gastric secretions from eroding the gastric epithelium?
Thick mucus layer.
What structural modifications increase surface area and what is the function of this?
What is the difference between villi and microvilli?
What are Peyer’s patches, where are they found, and what do they do?
Groups of lymphoid tissue in intestine – play an important role in immune response in the ileum (latter end of intestine).
What is the function of the central lacteal in intestinal villi?
Transport fats to the lymph.
Why is the pancreas considered a mixed gland?
It secretes both enzymes and hormones.
What are the secretions of the exocrine pancreas and what do they do?
What are the secretions of the endocrine pancreas and what do they do?
Where does most nutrient absorption occur in the GI tract?
What is the function of the liver?
Produce bile and regulate nutrient levels and metabolism.
What major blood vessels supply the liver with blood, how do they differ, and what is their function?
What is the gallbladder and what does it do?
Stores bile to be used in intestines.
What is the function of the large intestine?
Absorption of water and breakdown products from bacteria.
What is amylase, where is it secreted, and what does it do?
Which endocrine organs are considered mixed glands and why?
How are hormones classified chemically?
What is a preprohormone? A prohormone? Where are each of these found in the cell and how do they differ from a mature hormone?
What types of signal transduction do peptide hormones use? How does this differ from steroid hormones?
What is a binding protein? What types of hormones use these and why are they important?
What is down regulation and how does it affect the response to a particular hormone?
What hormones are involved in water homeostasis? Where are they produced and what do they do?
The only hormone involved in water homeostasis is ADH or vasopressin. It targets the kidney to reduce the amount of water excreted. It is produced in the hypothalamus and released via the posterior pituitary. ANP also produces higher excretion levels of water.
What hormones are involved in sodium homeostasis? Where are they produced and what do they do?
Aldosterone and atrial natriuretic peptide (ANP). ANP is produced in special myocardial cells and causes the excretion of sodium. Aldosterone is synthesized in the adrenal cortex and promotes the reabsorption of sodium from the kidneys.
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