Physiology Lecture Exam 3

What is the difference between intra alveolar pressure and intra pleural pressure?

Intra alveolar pressure is the pressure within the alveoli, while intra pleural pressure is exerted outside the lungs within the thoracic cavity.

What keeps the lungs stretched apart?

Intrapleural fluid cohesiveness.

What is the transmural pressure gradient?

It is the difference where intra alveolar pressure is greater than intrapleural pressure, which helps expand the lungs.

How does air flow into and out of the lungs?

Air flows due to changes in intra alveolar pressure brought about by respiratory muscle activity.

What is Boyle's Law?

P1V1=P2V2; at constant temperature, the pressure exerted by a gas varies inversely with the volume of the gas.

What branch of the ANS controls bronchoconstriction and bronchodilation?

Bronchoconstriction is controlled by the parasympathetic branch, and bronchodilation is controlled by the sympathetic branch.

What is alveolar surface tension?

It is the tension or force exerted by water molecules on the alveolar surface, opposing the expansion of the alveoli.

What is pulmonary surfactant and which cells secrete it?

Pulmonary surfactant lowers surface tension and is secreted by alveolar type II cells.

What is the difference between obstructive and restrictive lung disease?

Obstructive lung disease involves difficulty emptying the lungs, while restrictive lung disease involves difficulty filling them.

What is dead space volume?

It is the amount of air in the conducting pathways that is not available for gas exchange.

Define partial pressure.

It is the individual pressure exerted independently by a particular gas within a mixture of gases.

What factors influence gas diffusion?

Surface area, thickness of barrier, and diffusion coefficient of gas.

How is oxygen transported in the blood?

Oxygen is transported dissolved in plasma and bound to hemoglobin.

What is the law of mass action?

A reversible reaction is determined by the concentrations of the molecules involved.

What does the oxygen-Hb dissociation curve tell us?

It illustrates the relationship between oxygen saturation of hemoglobin and the partial pressure of oxygen.

What is the BOHR effect?

Both CO2 and H+ bind to allosteric sites on hemoglobin, altering its affinity for O2.

What is the function of 2,3 DPG?

It decreases the affinity between hemoglobin and oxygen.

How is carbon dioxide transported in the blood?

Carbon dioxide is transported physically, bound to hemoglobin, and as bicarbonate.

What is the HALDANE effect?

Removal of O2 from hemoglobin facilitates the uptake of CO2 and H+.

What is hypoxia?

Hypoxia is insufficient O2 at the cellular level.

What is hyperoxia?

Hyperoxia is above the normal arterial PO2, often due to breathing supplemental O2.

What is hypercapnia?

Hypercapnia is excess CO2 in the arterial blood, often caused by hypoventilation.

What is respiratory acidosis?

Respiratory acidosis is characterized by hypercapnia, or excess CO2 generated H+.

What is the difference between a tropic hormone and a non tropic hormone?

Tropic hormones stimulate other glands to release hormones, while non tropic hormones directly affect target organs.

What is the common precursor for all steroid hormones?

Cholesterol.

What hormone is secreted by the pineal gland?

Melatonin, which regulates sleep-wake cycles.

What hormones are secreted by the anterior pituitary gland?

They include growth hormone, prolactin, and adrenocorticotropic hormone (ACTH).

What hormones are secreted by the hypothalamus?

They include releasing and inhibiting hormones that regulate the anterior pituitary.

What hormones are secreted by the posterior pituitary?

Oxytocin and vasopressin (ADH), produced in the hypothalamus.

What are the functions of the thyroid gland?

It regulates metabolism, growth, and development.

What is calcitonin and what cells secrete it?

Calcitonin is a hormone that lowers blood calcium levels, secreted by parafollicular cells of the thyroid.

What are T3 and T4?

They are thyroid hormones that regulate metabolism.

What are the 3 layers of the adrenal gland cortex?

The zona glomerulosa, zona fasciculata, and zona reticularis, producing various hormones.

What hormone classes are secreted by the adrenal glands?

Steroid hormones, including glucocorticoids, mineralocorticoids, and androgens.

What are the functions of aldosterone?

Aldosterone regulates sodium and potassium levels, influencing blood pressure.

What molecules stimulate the growth of the zona glomerulosa?

Angiotensin II and plasma potassium levels.

What is the function of cortisol?

Cortisol regulates metabolism and the body's response to stress.

Cortisol is regulated by what hormone?

Adrenocorticotropic hormone (ACTH).

What is the function of DHEA?

DHEA is an androgen that contributes to the development of male and female secondary sexual characteristics.

What hormone regulates metabolism?

Epinephrine

Where in the adrenal glands is epinephrine and norepinephrine released from?

Adrenal medulla

What are the metabolic effects of epinephrine?

Increases blood glucose levels, stimulates fat breakdown, and increases heart rate.

What cells secrete insulin and what is its function?

Beta cells; regulates blood glucose levels.

What causes insulin to be released?

Increased blood glucose levels.

What is the difference between type I and type II diabetes?

Type I is autoimmune destruction of beta cells; Type II is insulin resistance.

What cells secrete glucagon and what is its function?

Alpha cells; raises blood glucose levels.

What are the vascular, combined vascular/tubular, and tubular components of the nephron?

Glomerulus, peritubular capillaries, and renal tubules.

What are the 3 structures that filter blood plasma into filtrate/urine?

Glomerulus, Bowman's capsule, and renal tubules.

What are the factors that move water into and out of the glomerulus?

Hydrostatic pressure and osmotic pressure.

What does GFR stand for?

Glomerular Filtration Rate.

What is Kf?

Filtration coefficient; depends on surface area and permeability.

How is capillary blood pressure regulated to maintain a constant GFR?

Through myogenic response and tubuloglomerular feedback.

Can the macula densa detect changes in GFR?

Yes, it can adjust afferent arteriole diameter.

How can the GFR autoregulatory mechanism be harmful?

It can lead to renal damage under extreme conditions.

Describe the extrinsic control mechanism for blood pressure and its relation to renal function.

Hormonal and neural mechanisms that affect blood pressure and renal perfusion.

How can Kf be modulated?

By changing the surface area or permeability of the glomerular capillaries.

What cells serve as pre-capillary sphincters in the glomerulus?

Afferent arterioles.

How can the permeability of the glomerulus be modulated?

By changes in podocyte structure and mesangial cell contraction.

What reabsorbed molecules rely on sodium reabsorption?

Glucose and amino acids.

What secreted molecules rely on sodium reabsorption?

Potassium and hydrogen ions.

Where is the sodium potassium ATPase pump located?

Basolateral membrane of renal tubule cells.

How is sodium reabsorption regulated?

By aldosterone and atrial natriuretic peptide.

How are glucose and amino acids reabsorbed?

Through secondary active transport with sodium.

What is Tm?

Transport maximum for substances reabsorbed in the kidneys.

What determines Tm?

Number of transporters available and substrate concentration.

What does parathyroid hormone regulate?

Calcium levels in the blood.

How are potassium and hydrogen ion secretion related?

Increased potassium secretion often leads to increased hydrogen ion secretion.

What does the vertical osmotic gradient refer to?

The difference in osmolarity between the renal cortex and medulla.

What parts of the tubule are impermeable vs permeable to water?

Thin descending limb is permeable; thick ascending limb is impermeable.

How does ADH make the collecting tubules permeable to water?

By increasing aquaporin channels in the membrane.

What can result in renal failure?

Diabetes, hypertension, and glomerulonephritis.

What cells initiate slow wave potentials?

Interstitial cells of Cajal.

What 2 nerve plexuses modulate digestive tract activity?

Myenteric (Auerbach's) and submucosal (Meissner's) plexus.

What enzymes are utilized in the mouth?

Salivary amylase and lingual lipase.

What stomach factors determine how fast the stomach empties its contents?

Volume of chyme, nervous stimulation, and fluidity of chyme.

What duodenum factors halt gastric emptying?

Fat, acid, hypertonicity, and distension.

What hormones are involved in inhibiting gastric emptying?

Secretin and CCK.

What 3 cell types are found in the gastric pits of the fundus and body?

Mucous neck cells, chief cells, and parietal cells.

What cell in the stomach secretes gastrin?

G cells.

What is the function of enterokinase?

Activates trypsinogen to trypsin.

What is the function of the gall bladder?

Stores and concentrates bile between meals.

What is the function of bile?

Emulsifies fats to increase surface area for digestion.

What are brush border enzymes?

Enzymes that complete protein and carbohydrate digestion.

What is the function of having villi and microvilli in the small intestines?

Increase surface area for absorption.

What are the 3 sections of the small intestines?

Duodenum, jejunum, ileum.

What muscles regulate the temperature of the testes?

Cremaster and dartos muscles.

What are the functions of Sertoli cells and Leydig cells?

Sertoli cells support sperm development; Leydig cells produce testosterone.

What is the acrosome?

A modified secretory vesicle filled with enzymes.

What is the function of the epididymis?

Maturation and storage of sperm.

What are the 3 sections of the male urethra?

Prostatic, membranous, and spongy.

What are the spongy masses in the penis?

Corpora cavernosa and corpus spongiosum.

What ligaments support the penis?

Fundiform and suspensory ligaments.

What ligaments support the ovaries?

Suspensory ligament and ovarian ligament.

What is the function of the corpus luteum?

Produces hormones after ovulation.

What are the corona radiata and zona pellucida?

Layers surrounding the oocyte.

What are the 3 sections of the fallopian tubes?

Infundibulum, ampulla, isthmus.

What are the 3 layers of the uterus wall?

Perimetrium, myometrium, endometrium.

What are the two layers of the endometrium?

Stratum functionalis and stratum basalis.

What is the function of the myoepithelial cells of the mammary glands?

Provide contractile force to move milk.