BIOL 2160 Final Exam

A deficiency in cholesterol will have the largest effect on the activity of which organ?

Liver

A liver cell in your body that has become infected by a virus would present an antigen on its own:

Class I MHC complex

A person who has had their gall bladder removed must closely monitor their intake of what?

fats

Allergies are a result of excessive release of what?

Histamine

An epitope is part of:

An antigen

Bile salts are made from:

Cholesterol

Both B cells and T cells have receptors for antigens on their membranes (T/F)

True

Cytotoxic T cells release perforin, which does what?

Forms pores in cell membranes

During a record-setting performance at the bar, you manage to consume 1,000 mLs of alcohol. About how much water will you eliminate in your urine?

4,000 mLs

Eating a meal that is high in protein will result in increased release of which pancreatic enzyme?

Chymotrypsin

Failure of the pancreas to secrete adequate levels of sodium bicarbonate might have which of the following consequences?

Damage to the small intestine due to exposure to acidic chyme

Helper T cells are involved in:

Both humoral and cell-mediated immunity

How do memory B cells help you avoid getting the same illness twice?

By forming plasma cells and releasing antibodies

If you were to measure the pH of chyme in the duodenum, and found it to be between 7 and 8, would this promote, or delay further emptying of gastric contents?

Promote

In which part of the nephron is Na+ not reabsorbed?

Descending limb of the Loop of Henle

Increased blood flow to the site of injury is a result of __________ being released by mast cells.

Histamine

Increased vasopressin levels might be attributed to improper functioning of which digestive organ?

Large intestine

Reabsorption of ___________ in the proximal tubule is active.

Na+

Select the incorrect statement about ADH.

- It is secreted if the body fluids become hypertonic

- It is produced by the distal tubule

- It stimulates reabsorption of water

- It is not secreted if the body consumes large amounts of water

- It is also called vasopressin

- It is produced by the distal tubule

Some drugs are easily detected in the urine because of which process?

Secretion

The Na+-K+ ATPase transport system that plays a pivotal role in much of tubular reabsorption is located on the __________.

Basolateral membrane of tubular cells

The pharyngoesophageal sphincter is normally closed to prevent what?

Air from entering the esophagus during breathing

The purpose of the Loop of Henle is to establish a concentration gradient that will allow for the reabsorption of __________ in the distal tubule and collecting duct

water

Water reabsorption is under the control of vasopressin _______.

Only in the distal tubule and collecting duct

What is the purpose of cytokines in the inflammatory response?

Attract more phagocytic cells

What is the purpose of the Loop of Henle?

Maintain a chemical gradient

What percentage of plasma entering the glomerulus is unfiltered and leaves through the efferent arteriole?

80%

What percentage of the total Na+ that gets reabsorbed takes place in the proximal tubule?

67

When the extracellular fluid becomes too acidic, the tubular secretion of __________

Hydrogen ions increase

Where does 25% of the total Na+ reabsorbed take place?

Ascending limb of the Loop of Henle

Which cell type in the adaptive immune system would be most helpful in destroying cancerous cells in your body?

Cytotoxic T cells

Which cell type in the innate immune system would be most useful in battling cancerous cells?

Natural Killer cells

Which gastric hormone indirectly affects fat digestion?

Cholecystokinin (CCK)

Which is NOT a pancreatic hormone that is involved in protein digestion?

- Carboxypeptidase

- Aminopeptidase

- Chymotrypsin

- Trypsin

- Aminopeptidase

Which is reabsorbed at the proximal tubule?

- Glucose

- All of these

- Urea

- Amino acids

- None of these

- All of these

Which is the primary absorptive organ of the digestive system?

Small intestine

Which of the following is not a component of saliva?

- Amylase

- Mucus

- Water

- Lysozyme

- Pepsin

- Pepsin

Which of the following is not a function of the kidneys?

- Maintain appropriate CO2 levels in the blood

- Maintain proper plasma volume

- Regulation of the concentration of extracellular fluid ions

- Maintain water balance in the body

- None of the above

Maintain appropriate CO2 levels in the blood

Which of the following is not a step in transepithelial transport?

- Movement of the substance across the basolateral membrane of the tubular cell

- Movement of the substance through tight junctions of tubular cells

- Movement of the substance across the luminal membrane of the tubular cell

- Movement of the substance through the cytosol of the tubular cell

- Movement of the substance across the glomerular capillary wall

- Movement of the substance through tight junctions of tubular cells

Which of the following is NOT a type of autoimmune disease?

- All of the above

- Rheumatoid arthritis

- Type 1 Diabetes

- AIDS

- AIDS

Which of the following is NOT part of the humoral immune response?

- Activation of cytotoxic T cells

- Production of memory B cells

- Activation of helper T cells

- Secretion of antibody molecules

- Activation of cytotoxic T cells

Which of the following is NOT part of your innate immunity?

- Lysozyme

- Mucus

- Skin

- T cell lymphocytes

- T cell lymphocytes

Which of the following is not usually one of the substances that is secreted during tubular secretion?

- K+

- H+

- Na+

- Organic ions

- Na+

Which of the following will NOT be recognized by T cell lymphocytes?

- None of the above

- Antigen presented by an antigen-presenting cell

- Un-bound antigen circulating in the blood

- Antigen presented by infected cell

Un-bound antigen circulating in the blood

Which part of an antibody physically makes contact with antigens?

Variable region

Which process is thought to control interferon release?

Fever

Which tissue layer of the digestive tract helps prevent damage from friction due to digestive motility?

Serosa

Which type of lymphocyte divides during the humoral immune response?

B cell

Why would drinking sea water make you more dehydrated?

Increased Na+ in the filtrate would lead to increased secretion of water in the distal tubule

The colon is part of which digestive organ?

-small intestine

-liver

-large intestine

-large intestine

HIV is a virus specifically known to attack what type of immune cell?

-Plasma B cells

-Memory T cells

-Helper T cells

-Cytotoxic T cells

Helper T cells (CD4)

Constipation is a consequence of which organ improperly functioning?

-Small Intestine

-Stomach

-Kidneys

-Large Intestine

-Gallbladder

Large Intestine

If a person were to have complications with gallbladder function, what kinds of foods should they stay away from?

-Fruits

-Fats

-Salts

-Poultry

Fats/Lipids

Increased urine production and excretion is a result from which biological process?

-Inhibition of ADH secretion

-Low TSH levels

-Decreased aldosterone

-Increased ADH presence

Inhibition of ADH secretion

What role does vasopressin have on the function of the membrane of the distal tubule?

-Increases fluid output to the collecting duct

-Decreases water reabsorption into the peritubular capillaries

-Has little to no effect on water maintenance

-Generates a greater flow of water back into the blood

Generates a greater flow of water back into the blood

Passive Reabsorption

No energy required; substance moves down electrochemical or osmotic gradients.

Active Reabsorption

Requires energy if any step in transepithelial transport is against an electrochemical gradient.

Na+ Reabsorption

Essential for overall reabsorption (80% of kidney's energy use); occurs in proximal tubule (67%), ascending limb of loop of Henle (25%), and distal/collecting tubules (8%, hormonally controlled). Drives reabsorption of glucose, amino acids, H2O, Cl-, and urea, and plays a role in concentrating urine and regulating ECF volume.

Glucose and Amino Acid Reabsorption

Reabsorbed by sodium-dependent, secondary active transport.

Key Secreted Substances

H+ (acid-base balance; in proximal, distal, collecting tubules), K+ (maintains membrane excitability; in distal, collecting tubules), and organic ions (in proximal tubule).

Vasopressin (ADH)

Hormone controlling variable water reabsorption in the distal tubule and collecting duct by inserting aquaporins. Produced in hypothalamus, stored in posterior pituitary. Secretion increases during water deficit (increases water reabsorption) and decreases during water excess.

Micturition

Process of urine elimination. Stimulated by stretch receptors in the bladder wall, leading to bladder contraction and relaxation of the external urethral sphincter.

Four Functions of Digestive System

Motility, Secretion, Digestion, Absorption.

Mucosa

Innermost layer lining the luminal surface, highly folded to increase absorptive area.

Serosa

Outer layer that secretes serous fluid for lubrication and support of digestive organs.

Saliva Composition & Functions

99.5% H2O, 0.5% electrolytes/protein. Functions: Salivary amylase (starts carbohydrate digestion), moistens food for swallowing, antibacterial action (lysozyme), solvent for taste, cleans mouth/teeth, bicarbonate buffers, lingual lipase (starts fat breakdown).

Secretin

Stimulated by acidic chyme in duodenum; pancreas releases bicarbonate.

Gastrin

Stimulated by protein in duodenum; chief/parietal cells secrete more HCl.

Cholecystokinin (CCK)

Stimulated by fat/protein in duodenum; pancreas releases lipase/proteolytic enzymes.

Phases of Gastric Secretion

Cephalic (stimuli in head), Gastric (food in stomach), Intestinal (inhibitory as chyme enters small intestine).

Pancreas

Secretes pancreatic juice containing pancreatic enzymes (proteolytic enzymes like trypsin, chymotrypsin, carboxypeptidase; pancreatic amylase; pancreatic lipase) and aqueous alkaline solution.

Pancreatic Lipase

Only enzyme in the entire digestive system that can digest fat.

Liver - Bile Production

Liver actively secretes bile, which is stored and concentrated in the gallbladder. Bile salts (cholesterol derivatives) emulsify fats. Most bile salts are reabsorbed.

Small Intestine - Adaptations for Absorption

Permanent circular folds, villi (microscopic finger-like projections) greatly increase surface area. Lining replaced every three days.

Absorption

ransfer of small digested units, water, vitamins, and electrolytes from digestive tract lumen into blood or lymph, mostly in the small intestine.

Lymphocytes (Main Types)

B lymphocytes (B cells) and T lymphocytes (T cells); both have antigen receptors.

Lingual Lipase

Enzyme produced by the tongue that begins the breakdown of long-chain fats into smaller pieces in the mouth.

Pepsin

Enzyme in the stomach (activated from pepsinogen by HCl) that begins the digestion of proteins into smaller polypeptides.

Pancreatic Amylase

Enzyme secreted by the pancreas that continues carbohydrate digestion in the small intestine, converting polysaccharides into disaccharides (e.g., maltose).

Disaccharidases (Brush Border Enzymes)

Enzymes located on the epithelium of the small intestine (brush border) that break down disaccharides (e.g., maltose, sucrose, lactose) into monosaccharides.

Bile Salts

Derivatives of cholesterol secreted by the liver and stored in the gallbladder; they emulsify large fat globules into smaller fat droplets in the small intestine, increasing surface area for lipase action.

Saliva

Secretion from salivary glands containing water, electrolytes, salivary amylase, mucus, lysozyme, and bicarbonate buffers.

Hydrochloric Acid (HCl)

Secreted by parietal cells in the stomach; activates pepsinogen to pepsin, denatures proteins, breaks down connective tissue, and kills microorganisms.

Tubular Secretion (Urinary System)

A basic renal process involving the selective transfer of substances from the peritubular capillaries into the tubular lumen of the nephron for elimination in urine. Important for removing H+, K+, and organic ions.

Antibodies (Immunoglobulins - Secretion in Immune System)

Y-shaped protein molecules secreted by plasma cells (differentiated B cells) that bind specifically to antigens, neutralizing them or marking them for destruction.

Antigen Receptors (Macromolecule)

Proteins found on the plasma membranes of B cells and T cells that recognize and bind to specific antigens.

MHC Molecules (Major Histocompatibility Complex - Macromolecule)

Cell surface proteins that present antigen fragments to T cells. Class I MHC are on all nucleated cells; Class II MHC are on antigen-presenting cells (APCs).

Urea Reabsorption (Urinary System)

Passive diffusion of urea from the kidney tubule back into the blood, driven by the concentration gradient created by water reabsorption.

Glucose and Amino Acid Reabsorption (Urinary System)

Reabsorbed in the proximal tubule of the kidney by sodium-dependent, secondary active transport from the filtrate back into the blood.

Water Reabsorption (Urinary System)

Process in the kidney tubules where water is moved from the filtrate back into the blood. 65% is obligatory in the proximal tubule; variable reabsorption occurs in the distal tubule and collecting duct, controlled by vasopressin (ADH).

Interferons (Secretion in Immune System)

Proteins released by virally-infected cells that help healthy cells resist viral infection and can activate macrophages.

Histamine (Secretion in Immune System)

hemical released by mast cells (and other cells) that causes vasodilation and increased capillary permeability during inflammatory and allergic responses.

Secretin (Intestinal Hormone)

Hormone stimulated by acidic chyme in the duodenum; stimulates the pancreas to release bicarbonate buffer to neutralize the acid.

Pancreatic Nucleases

Enzymes secreted by the pancreas that digest DNA and RNA into nucleotides in the small intestine.

Pancreatic Proteolytic Enzymes (Trypsin, Chymotrypsin, Carboxypeptidase)

Enzymes secreted by the pancreas that digest proteins and polypeptides into smaller polypeptides and amino acids in the small intestine.