CSCC BIO 2301 Lecture Exam 4

Approximately 85% of the renal nephrons are which type? Name the types.

Cortical Nephrons - 85% located almost entirely in the cortex of kidney

Juxtamedullary Nephrons - 15% located closer to the cortical medullary junction. Have a better ability to reabsorb water (important during dehydration)

The type of nephron that produces a hypertonic (high solute concentration) urine is which of these above types?

Juxtamedullary Nephrons

Place the following in correct sequence.

1. Collecting duct

2. Distal convoluted tubule

3. Glomerulus

4. Proximal convoluted tubule

5. Loop of Henle

6. afferent arteriole

7. renal pelvis

8. minor calyx

Afferent arteriole, glomerulus, proximal convoluted tubule, loop of Henle, distal convoluted tube, collecting ducts, minor calyces, major cayleces, renal pelvis

When afferent arterioles of the kidney DILATE, glomerular filtration rate is affected how? explain:

When the afferent arterioles dilate, blood flow increases into glomerulus. The more blood that goes through the glomerulus, the more blood that is able to be filtered.

Please explain GFR regulation in terms of:

A. the myogenic mechanism

B. the tubuloglomerular mechanism

C. the renin angiotensin system

Myogenic - Increases in systemic blood pressure causes smooth muscle to stretch in the afferent arteriole, which causes muscles to contract harder. This vasoconstriction decreases the volume of blood flowing into the glomerulus.

Tubuloglomerular - This is based on the amount of fluid in the distal tubules. If fluid is decreases, macula dense cells stimulate vasodilation of afferent arteriole to increase blood flow. If fluid is increased, macula dense cells stimulate vasoconstriction of afferent arteriole hindering blood flow to glomerulus. This decreases GFR to allow more time for filtrate processing

Renin Angiotensin System - If BP is low, GFR decreases, macula densa and juxtaglomerular cells detect decreased stretch of tubules and decreased sodium in filtrate. Juxtamedullary cells secrete renin. Renin converts plasma protein angiotensin to angiotensin I. Angiotensin I is activated as it passes through the lungs to angiotensin II by enzyme called ACE. If BP is high, GFR is high. ANF is secreted by cells in the atria. ANF Suppresses ADH and Aldosterone.

How is the fluid in Bowman's capsule similar or different to plasma ? Think size!

The glomerular filtrate has the same composition of plasma except that it does not contain any of the larger components, such as plasma proteins or cells.

What two hormones regulate GFR

Angiotensin II and ANF

What do Macula densa monitor and where are they found:

Intertubular salt concentration

Distal convoluted tubule

How much glucose is found in the filtrate of the collecting duct in a normal individual?

None

Which cells produce renin? Where is A.C.E. produced?

Juxtamedullary cells

Capillary blood vessels in the lung

If blood pressure falls, what does ADH, Aldosterone and renin do to compensate?:

-Juxtamedullary cells detect decreased stretch/ decreased sodium in filtrate.

-Juxtamedullary cells secrete renin.

-Renin converts Angiotensin to Angiotensin I.

-Angiotensin I is activated as it passes through the lungs by enzyme called ACE.

- Angiotensin II vasoconstricts systemic arterioles (increases resistance), stimulates the release of aldosterone (raises blood volume), and stimulates ADH release (raises blood volume).

Which substance from question 23, directly stimulates the reabsorption of Na+ ions?

Aldosterone and ADH

ADH controls the reabsorption of water at which part of the nephron?

Collecting ducts. This occurs based on needs of the body.

Most reabsorption occurs in which part of the nephron?

Proximal convoluted tubule

The capillary network that surrounds the convoluted tubules is called the:

Peritubular Capillaries

Can you name the hormones that would increase urine output:

ADH and Aldosterone

Through what transport mechanism is sodium reabsorbed from the kidney tubules?

Active transport. If we reabsorb more positive ions, negative ions will follow passively because of the pull of charge (electromagnetic gradient) (chloride and bicarbonate are absorbed this way)

When blood pH drops towards acidic ends of the homeostatic range, the renal tubule cells actively secrete hydrogen ions into the filtrate and retain more _____________________ ions.

Potassium

How can the micturition reflex be voluntarily inhibited? What will you do, or what will you activate?

There are two sphincters of the bladder; internal (involuntary smooth muscle), external (voluntary skeletal muscle). Choosing to contract the external sphincter inhibits micturition.

Explain the following for the process of micturition?

A. parasympathetic or sympathetic

B. what part of spinal cord

C. muscles involved

D. sphincters involved

A. Afferent sensory and Efferent motor return to the bladder via the pelvic nerve (parasympathetic)

B. Sacral region

C. Detrusor

D. Internal and external

If caffeine reduces the release of anti-diuretic hormone (ADH), then caffeine might cause what changes to urine output?

ADH causes the kidneys to release less water, decreasing the amount of urine produced. If caffeine prevents the releases of ADH, a more dilute urine would be produced potentially leading to dehydration.

Where is the thirst center located and what would activate it?

Hypothalamus

ADH

Increased serum osmolarity should cause what compensations or releases in the following:

A. Thirst

B. ADH

C. Aldosterone

A. thirst - Increased

B. ADH - Increased

C. Aldosterone - Decreased

How do the following factors affect urine volume?

A. temperature

B. hemorrhage

C. ADH levels

D. BP

Temperature - If you are hot, you produce a small volume of urine to conserve water

Hemorrhage - If you lose blood, your BP drops, reducing the volume of filtrate, reducing urine volume

ADH levels - ADH conserves water, if there is more ADH, there is less urine

BP - If blood pressure is low, there is less urine volume as there is less being filtered

What is the normal osmolarity range of body fluids:

300 mOsm

The electrolyte, Calcium, is primarily regulated by what hormone? (Promotes kidney reabsorption of calcium when levels are low in the blood, bone destroying)

Parathyroid Hormone (PTH)

Calcitonin promotes calcium secretion

Explain the relationship of [H+], to pH number, to carbon dioxide levels regarding pH?

Carbon dioxide influences the pH of the blood by reacting with water to form carbonic acid (H2CO3), which can disassociate to form a H+ ion and a Hydrogen carbonate ion (HCO3-). Increasing the carbon dioxide levels in the blood therefore results in more H+ ions and a lower pH.

The pH range of urine is _____.

4.5-7.8

Name the major chemical buffer systems in the blood:

Carbonic acid Bicarbonate Buffer

Phosphate Buffer System

Protein Buffer System

What is the nephron?

Functional unit of the kidney

Know the difference between the parts of the renal corpuscle and renal tubule?

Renal corpuscle- glomerulus and glomerular capsule

Renal tubule - proximal convoluted tube, loop of henle, distal convoluted tubule

What are glomerular filtration, tubular secretion and tubular reabsorption? Where does each occur?

Glomerular Filtration - the first step in urine production filtering out most solutes (glomerular capillary)

Tubular reabsorption - the second step in urine production, almost all nutrients are reabsorbed by active transport (renal tubule)

Tubular secretion - the third step in urine production, where solutes and waste are secreted into the collecting ducts

How often does the kidney filter the blood? What is the average GFR?

The kidney is always filtering blood. The average GFR is 125 mil/min or 48 gal/day

What can increase/decrease GFR (think afferent arterioles)?

In a sympathetic episode, the afferent arterioles vasoconstricts, which helps to shunt or divert blood to heart and muscles. --> Urine formation decreases. This increases GFR due to high bp/osmolarity

During parasympathetic regulation, the afferent arterioles will vasodilate which will reroute blood back to the rest of the body, which will increase urine formation. This decreases GFR due to low BP/osmolarity.

Water, Sodium, Glucose and Urea... which do we reabsorb in large amounts and which do we excrete...

Reabsorbed - water, sodium, glucose

Secreted - sodium, urea, water

What does low/high tubular osmolarity mean... low/high plasma osmolarity?

The amount of particles total in the filtrate within the tubules

The amount of particles total in the plasma

What hormone causes Na to be retained in the distal convoluted tubule?

Aldosterone

Where does ADH act to conserve water loss?

Collecting ducts

If ADH increases/decreases, what happens to osmolarity?

ADH causes the kidneys to retain more water (conserve water).

If ADH increases, osmolarity decreases.

If ADH decreases, osmolarity increases.

If Aldosterone increases/decreases what happens to osmolarity?

Aldosterone increases sodium retention.

If Aldosterone increases, osmolarity increases.

If Aldosterone decreases, osmolarity decreases.

What is the most important factor to measure the health of the individual?

Diet

What is the correct recommendation for caloric intake of fats, carbs and proteins?

Fats - 25%-30% with no more than 10% of saturated fats

Carbs - 45%-65%

Proteins - 10%-35%

How much fiber should be ingested per day?

25-35 grams of fiber

Most of the carbohydrates we eat come from what sources.

Breads, cereal, crackers, flour, pasta etc.

Explain proteins, complete vs incomplete, essential vs. nonessential, and uses:

Complete - meets all of the body's amino acid requirements

Incomplete - nutritionally incomplete because they lack one or more essential amino acid

Essential - 9 of the 20 amino acids are referred to as essential and must be present in the diet because they cannot be synthesized in the body

Nonessential - the body can synthesize these amino acids from dietary proteins

Who should commonly be in a negative nitrogen balance? Positive?

Positive - Growing children and pregnant women

Negative - People going through physical or emotional stress

Sucrase, maltase and lactase are dipeptidases that are secreted by what organ?

Small Intestine

Name the function of the following:

Folic Acid

Folic Acid - production of DNA and RNA as well as metabolism of certain amino acids

Name the function of the following:

Vitamin B12

Vitamin B12 - energy metabolism as well as amino acid synthesis, relates to folic acid

Name the function of the following:

Vitamin D

Vitamin D - required for the reabsorption of calcium from the intestines

Name the function of the following:

Vitamin A

Vitamin A - component of rhodopsin and iodopsin. Important to cell differentiation and an antioxidant

Name the function of the following:

Vitamin C

Vitamin C - involved in biosynthesis including colleges. Involved in immune function and an antioxidant

Name the function of the following:

Calcium

Calcium - primary component of calcium phosphate (what makes up bone). Gives bone rigidity and hardness. Also regulates muscle cell contraction and the secretion of many neurotransmitters and hormones

Name the function of the following:

Potassium

Potassium - primary intracellular electrolyte, important to the activity of excitable cells

Name the function of the following:

Magnesium

Magnesium - important to ATP metabolism as well as an important role to the production of resting potentials

Name the function of the following:

Iodine

Iodine - essential component for thyroid hormones

Name the function of the following:

Chromium

Chromium - important for transport of insulin to the cells

An increase in blood insulin will do what to our hunger?

Hunger will decrease

Food intake is regulated by what brain area?:

Hypothalamus

What do the following chemical do in terms of satiety, hunger signals, and gastric motility?

A. Serotonin

B. Leptin

C. Neuropeptide Y

D. Cholecystokinin (CCK)

Serotonin - Neurotransmitter that may also deliver satiety signals (in large amounts may stimulate hunger)

Leptin - Acts on the hypothalamus to cause a reduction in food intake, inhibits neuropeptide Y, which makes you want to eat. Also stimulates metabolic rate

Neuropeptide Y- hypothalamic neurotransmitter that stimulates eating, released during exercise, fasting, and hyperglycemia

Cholecystokinin (CCK) - intestinal hormone secreted during food digestion that depresses hunger

The desire to eat dirt defines what disorder?

Pica

The enzyme amylase is produced by what organ(s).

Salivary glands and pancreas

Why do we need intrinsic factor?

Produced by the parietal cells, only stomach function essential to life. Is needed for the absorption of B12. Without it, B12 deficiency (pernicious anemia)

What do the following do to gastric secretions, motility.

a. Gastrin

b. GIP

c. Somatostatin

d. Secretin

Gastrin - stimulates gastric secretions/peristalsis. Most pronounced effects on HCL secretion.

GIP - decreases peristalsis and gastric secretions

Somatostatin - decreases peristalsis and gastric secretions

Secretin - decreases gastric secretions

Chief cells in gastric glands secrete what?

Pepsinogen (activated to pepsin by HCL)

Name the proteases or proteolytic enzymes that are secreted by the pancreas and digest proteins.

Trypsin, chymotrypsin, carboxypeptidase

What is the function of ghrelin?

Regulates hunger

The good cholesterol

HDL (high density lipoprotein)

Bacteria responsible for ulcer formation

Helicobacter pylori

Produced by stomach, binds to H2 receptors

Histamine

Digests emulsified fats

Intestinal lipase

Neutralizes acidic chyme

Bicarbonate

Digests proteins, produced by small intestines

Aminopeptidase

Produces bile

Liver

A bile pigment

Bilirubin

Inactive form of trypsin

Trypsinogen

In order to absorb fat, it must be in this form

Micelle

The defecation reflex is controlled by this part of the autonomic nervous system

Parasympathetic

Temperature that varies considerably

Shell

Temperature that is precisely regulated

Core

The temperature that is the absolute limit for life

110 degrees

If you relax the external anal sphincter, you ___________ defecation.

Facilitate

Site where pancreatic secretions enter duodenum

Hepatopancreatic ampulla

Stores and concentrates bile

Gallbladder

Digests maltose

Maltase

Stimulates insulin secretion from the pancreas

GIP

What is motility? What are the other digestive processes?

Movement of food from the mouth, through the pharynx, esophagus, stomach, small and large intestines, and out of the body.

Is salivation (and digestion) under sympathetic or parasympathetic control? What enzymes are found in saliva and what do they do?

It is under parasympathetic control

Salivary amylase is the enzyme found in saliva and it is used to begin the process of carbohydrate breakdown

What are the 3 stages of swallowing? Which are involuntary and where is it controlled?

Voluntary Phase - involves skeletal muscle. It occurs as you place the tip of the tongue against the hard palate and contract the tongue. This pushes the bolus of food into the oropharynx

Pharyngeal Phase - occurs when the bolus is in the oropharynx and the oropharynx is moist. It involves peristalsis of the pharynx while the uvula closes off the nasopharynx, the epiglottis closes off the trachea and the tongue blocks off the mouth, so that the food is pushed toward the esophagus. It is a parasympathetic event.

Esophageal Phase - occurs as the food is pushed down the esophagus by peristalsis. It is a parasympathetic event. When the food approaches the stomach, the gastroesophageal sphincter relaxes to allow the food into the stomach.

What are the mucus cells, chief cells and parietal cells? What do they secrete and what role does each have?

*All of these cells are exocrine function cells made in the stomach/secreted by the stomach.*

-Surface and neck mucus cells secrete mucus which protects the stomach lining and the mucosa from the acid

-Chief cells secrete pepsinogen and gastric lipase which aids with protein digestion

-Parietal cells secrete hydrochloric acid and intrinsic factor. IF aids with vitamin B12 absorption and HCL kills microbes in food and converts pepsinogen into pepsin.

Why do the stomach acids not destroy the stomach mucosa/lining?

The Surface and Neck mucus cells protect the mucosa and lining from being destroyed by stomach acid

What happens if intrinsic factor is not secreted? (THINK BLOOD)

If IF is not secreted than Vitamin B12 will be poorly absorbed which leads to pernicious anemia.

When does carbohydrate digestion begin? Protein? Fats?

-Carbohydrate digestion begins in the oral cavity during mastication.

-Protein digestion begins in the stomach once pepsin is activated

-Fat digestion begins in the small intestine by pancreatic lipase

When is the digestive materials called a bolus ... when are they considered chyme... feces?

Bolus - when the food is chewed up, ready to swallow

Chyme - when it passes from the stomach to small intestine

Feces - when all of the nutrients have been absorbed from chyme

What is the most important digestive function of the stomach? The small intestine and large intestine?

Stomach - holds and mixes food with acid and enzymes that break the food down into liquid and pastes

Small intestine - absorbing almost all of the nutrients you get from food into your blood stream

Large intestine - absorb water and salts from the material that has not been digested as food and get rid of waste products

Where do the pancreatic digestive enzymes enter the GI tract?

small intestine (duodenum)

What does pancreatic amylase, proteases (trypsin, chymotrypsin and carboxypeptidase) and lipase do?

Amylase - breaks down starch into sugar

Proteases - breaks down proteins into amino acids

Lipase - participates in the hydrolysis and digestion of fat

What does CCK and Secretin do?

CCK - regulates hunger signals

Secretin - regulation of gastric acid

What enzymes are found in the small intestine?

amylase, protease, lipase

What is bile? Where is produced? Where is it stored? What does it digest?

Breaks down fat

Liver

Gallbladder

Fats into fatty acids