Vocab 4 Temme

Question 1

exocrine gland

Answer 1

a gland that releases secretions outside an outer epithelial layer (Note: the space on the outside of an outer epithelium could still be within the body, such as the space within the gut tube.)

Question 2

amylase

Answer 2

an enzyme that catalyzes the breakdown of a glucose polymer called starch into maltose—the disaccharide composed of two glucose molecules. It is secreted by salivary glands and pancreas in response to the presence of food.

Question 3

pepsinogen

Answer 3

the inactive precursor to the protease called pepsin. It is formed in the chief cells of the stomach’s epithelium and is converted to pepsin by the action of hydrochloric acid.

Question 4

lipase

Answer 4

the enzyme that catalyzes the breakdown of triglycerides (or triacylglycerols) into fatty acids and glycerol.

Question 5

bile salts

Answer 5

chemical modifications of cholesterol that interact with both lipids and water (due to the addition of more polar and charged groups). They are produced by the liver and secreted into the small intestine where they help emulsify dietary fats.

Question 6

hepatic portal system

Answer 6

the circulatory arrangement where the capillaries surrounding the small intestine drain into
the portal vein that carries blood directly into the liver. As a consequence, the nutrients (and toxins) absorbed into the bloodstream move first past hepatic (liver) cells where they can be absorbed, stored, chemically modified, or excreted.

Question 7

gluconeogenesis

Answer 7

the chemical pathway that converts certain noncarbohydrate molecules, such as specific amino acids or lactate, into glucose molecules.

Question 8

ketogenesis

Answer 8

the chemical pathway within hepatic cells that converts fatty acids into some smaller water-soluble molecules, known collectively as ketone bodies, that can be readily used to generate ATP in other cells.

Question 9

glycogenesis

Answer 9

the chemical pathway that strings glucose molecules together to form a glucose polymer known as glycogen—the molecular arrangement used by animals to store glucose after meals.

Question 10

apoprotein

Answer 10

the term used to describe a protein that is normally attached to a second molecule other than a polypeptide. For example, an apolipoprotein is a protein that normally attaches to lipids.

Question 11

chylomicrons

Answer 11

water-soluble packages or droplets containing dietary triglycerides, cholesterol, phospholipids, and one copy of apolipoprotein B-48 (along with potentially other apolipoproteins picked up in circulation) that are synthesized in the endothelial cells of the small intestine, and enter general circulation through the lymphatic system

Question 12

VLDLs (very low density lipoproteins)

Answer 12

water-soluble packages or droplets containing either dietary or liver- synthesized triglycerides, cholesterol, phospholipids, and one copy of apolipoprotein B-100 (along with potentially other apolipoproteins picked up in circulation) that are used to transport these different forms of lipids from the liver to other body cells.

Question 13

enteric nervous system

Answer 13

a subdivision of the peripheral nervous system involved in the control of smooth muscle contractions and digestive secretions along the gastrointestinal system (gut tube). It is capable of coordinating many different gastrointestinal responses on its own, but it also it receives considerable innervation from the autonomic nervous system and thus is often considered a part of it.

Question 14

myenteric plexus

Answer 14

the portion of the enteric nervous system that lies between the two smooth muscle layers surrounding the gut tube.

Question 15

vagus nerve

Answer 15

the only paired cranial nerve that starts in the brainstem (within the medulla oblongata ) and extends down below the head, to the neck, chest and abdomen. Along with being a pathway for sensory visceral input into the CNS, it is the route by which preganglionic parasympathetic fibers reach the heart, bronchioles, and gut tube all the way from the neck down to the middle of the large intestine (the second segment of the transverse colon). (Note: It is also the pathway by which motor neurons reach certain neck skeletal muscles.)

Question 16

gastrin

Answer 16

the hormone released from G-cells located at the base (or antrum) of the stomach in response to decreasing acidity of stomach contents that stimulates pariental cells (located in other parts of the stomach) to secrete more H ions (that is, it stimulates gastric acid secretion).

Question 17

CCK (cholecystokinin)

Answer 17

a hormone released from I-cells located along the early part of the small intestine in response to detection of protein and fat that stimulates the pancreas to release digestive enzymes. (It also appears to play a role in the feeling of satiation after a meal.)

Question 18

secretin

Answer 18

a hormone released from S-cells located along the early part of the small intestine in response to intestinal contents being too acidic that stimulates bicarbonate secretion (in the pancreas and perhaps the Brunner’s gland. )

Question 19

insulin

Answer 19

a hormone released by pancreatic beta cells largely in response to increasing blood glucose levels (as well as some of other factors) that promotes the absorption of glucose and amino acids from the plasma into cells (especially adipose and resting skeletal muscle cells), along with turning on a variety of enzymes involved in storage and growth.

Question 20

glucagon

Answer 20

a hormone released by pancreatic alpha cells in response to lower blood glucose levels that stimulates liver cells to increase the release of glucose from storage (glycogenolysis) and synthesize new glucose molecules from noncarbohydrate precursors (gluconeogenesis), as well as stimulating adipose cells to release fatty acids from storage (lipolysis).

Question 21

parathyroid hormone

Answer 21

a hormone released from the parathyroid gland in response to decreasing blood calcium levels that acts to reverse this trend by (directly or indirectly) increasing: (1) the release of calcium ions from storage in bones, (2) the absorption of calcium ions in the small intestines, and (3) the reabsorption of calcium ions from kidney filtrate.

Question 22

1,25-OH2 Vitamin D3 (1,25-dihydroxychoecalciferol or calcitriol)

Answer 22

the active form of vitamin D whose synthesis is controlled by the presence of parathyroid hormone, and that promotes the absorption of more calcium from gut contents within small intestine.

Question 23

lysozyme

Answer 23

an enzyme found in saliva, tears, and sweat that can disrupt the function of certain types of bacteria by splitting sugars off their (peptidoglycan) cell wall.

Question 24

leukocyte

Answer 24

a general term for all the different types of white blood cells

Question 25

macrophages

Answer 25

a form of white blood cell that develop from monocytes to become phagocytic cells that take up positions throughout the body (as sentries). Once detecting entering bacteria (or other types of invaders) they both engulf them and release chemical signals that trigger a local inflammatory response.

Question 26

neutrophils

Answer 26

a form of white blood cell found in circulation that responds to inflammatory signals and is able to phagocytize pathogens (among other things), release toxic molecules, and release other chemical signals.

Question 27

complement system

Answer 27

a set of plasma proteins that act together to remove certain forms of pathogens within interstial space. It works by either coating a pathogen with proteins that facilitate removal by phagocytes or by killing the pathogen directly (by punching holes in cell membranes via the membrane attach complex).

Question 28

C3 convertase

Answer 28

the enzyme complex that catalyzes a crucial step in complement activation—the deposition of large numbers of C3 molecules on a cell’s surface, which tags the cell for removal by phagocytes or starts the assembly of the membrane attach complex.

Question 29

opsonization

Answer 29

the conversion of pathogens that are potentially unrecognizable by phagocytic cells (e.g., macrophages, neutrophils), into ones that can be recognized by coating or tagging them with a protein (such as C3b or antibodies).

Question 30

mast cells

Answer 30

large white blood cells found in connective tissue through the body that respond to certain chemicals by releasing a variety of signal molecules including histamine (which leads to vasodilation and increasing permeability of local blood vessels).

Question 31

cytokines

Answer 31

proteins made by one type of cell that influence the behavior or development of other cells. (Note: cytokines made by leucocytes are commonly called interleukins (IL), even though name is now somewhat misleading due to the fact that many interleukins have been found to be produced by a wide variety of body cells.)

Question 32

interferons

Answer 32

cytokines that generally induce cells to resist viral replication by shutting down protein synthesis.

Question 33

antigen

Answer 33

any small peptide presented by an MHC receptor, which, as a consequence, can potentially stimulate an acquired immune response. (Note: the word originated from the notion of being something that could stimulate antibody generation. It is now known, however, that an antigen can stimulate other forms of acquired immune responses besides antibody production. )

Question 34

antigen-presenting cell

Answer 34

a cell that specializes in degrading proteins and then presenting small peptides (antigens) on MHC receptors in a way that can potentially initiate an acquired immune response.

Question 35

Class II MHC

Answer 35

a form of cell surface receptor found only on antigen-presenting cells that presents antigens from proteins brought in from the outside of the cell via endocytosis (phagocytosis),

Question 36

Class I MHC

Answer 36

a form of cell surface receptor found on nearly all types of body cells that presents antigens from proteins produced within the cell presenting them.

Question 37

antibodies

Answer 37

a group of protein structures that originally start as cell surface receptors on B cells with hypervariable binding sites (thus antibodies on different B cells will tend to bind with different molecules). However, once a B cell becomes activated (undergoes clonal expansion and differentiation in plasma cells) numerous copies of this B cell’s specific antibody are secreted into interstitial space, where they can bind with whatever invading organism (or other structure) played a role in triggering this instance of B cell activation.

Question 38

plasma cell

Answer 38

the cell type that an activated B cell turns into once it goes through clonal expansion and differentiation. Each plasma cell specializes in the production and secretion of a specific type of antibody.

Question 39

SRY gene

Answer 39

the gender-determining gene found on mammalian Y chromosomes that codes for a protein that steers development towards becoming male.

Question 40

hCG (human chorionic gonadotropin)

Answer 40

a peptide hormone produced by the developing placenta and released into maternal circulation that acts to prevent the disintegration of the corpus luteum and thereby maintain maternal progesterone production for longer than would occur otherwise. (Progesterone in turn acts to allow the placenta and embryo to continue to develop by maintaining the endometrial lining of the uterus.)

Question 41

hCS (human chorionic somatomammotropin)

Answer 41

a peptide hormone produced by the developing placenta and released into maternal circulation that acts to block the actions of maternal produced insulin, and thus potentially increases the glucose (and other nutrient) supply available to the developing embryo/fetus.

Question 42

prolactin

Answer 42

a peptide hormone released from the anterior pituitary associated with lactation (among other things). For instance, during breastfeeding the act of an infant suckling a nipple stimulates maternal production of prolactin, which in turn stimulates lactogenesis (milk production) in preparation for the next feed.