Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
119 Cards in this Set
- Front
- Back
|
What are the 3 types of hormones?
|
1. peptides or proteins
2. steroid 3. amine |
|
|
What is a peptide or protein hormone?
|
-water soluble
-transported by vesicles out of the cell that made them -peptide hormone receptors are located on the surface of target cells -ex. growth hormone, insulin |
|
|
What is a steroid hormone?
|
-lipid soluble/ membrane permeable
-can diffuse out of the cell that made them -can diffuse into target cells -must be bound to carrier proteins in the blood -receptors for lipid soluble hormones are inside cell (cytoplasm or nucleus) -ex. estrogen |
|
|
What is an amine hormone?
|
-derivative of amino acid, tyrosine
-some water soluble, some lipid soluble -ex. epinephrine (adrenaline) |
|
|
What are the 3 domains for receptors for peptide/water soluble hormones?
|
1. binding domain- outside plasma membrane
2. transmembrane domain- anchors the receptor in the membrane 3. cytoplasmic domain- extends into the cytoplasm of the cell (initiates target cells response by activating enzymes like protein kinase or protein phosphates |
|
|
What is an endocrine cell?
|
a cell that secretes hormones
|
|
|
What does the posterior pituitary do?
|
releases two hormones:
-antidiuretic hormone -oxytocin made by neurons in the hypothalamus (neurohormones) and are packaged in vesicles |
|
|
What does the anterior pituitary do?
|
-controlled by neurohormones from the hypothalamus
-releases 4 tropic hormones (controls activities of other endocrine glands) ->they are peptide/protein hormones (each produced by a different type of pituitary cell) anterior pituitary also releases protein hormones that are not tropic -growth hormone, prolactin, endorphins, ect. |
|
|
What are the Islets of Langerhans?
|
-the pancreas endocrine part(~1%)
alpha- produce Glucagon (15-20%) beta- produce insulin (65-80%) both are destroyed in type one diabetes |
|
|
Control of blood glucose:
|
-after a meal, blood glucose levels rise (beta cells release insulin)
-insulin stimulates cells to use glucose and convert it to glycogen (muscle tissue) and fat (adipose tissue) -blood glucose falls, pancreas stops releasing insulin, cells switch to glycogen and fat for energy -if blood glucose falls too low, alpha cells release glucagon(stimualtes liver to convert glycogen back to glucose) |
|
|
How can insulin cause increased uptake of glucose?
|
-insulin triggers the exocytosis of intracellular vesicles containing the glucose transporter GLUT 4
-this results as an increased number of GLUT 4 molecules in the plasma membrane |
|
|
What are the two types of diabetes?
|
1. due to autoimmune destruction of insulin producing cells (pancreatic beta cells) 10%
2. due to "insulin resistance" caused by lack of sufficient functional insulin receptors on target cells 90% |
|
|
What is an animals metabolic rate?
|
the measure of the overall energy needs that must be met by the animals food
|
|
|
How is energy stored in an animal?
|
-carbohydrates: stored in liver and muscle cells as glycogen (total store=one day's energy requirement)
-fat: more energy per gram than glycogen and stored with little water, more compact) -protein: not used to store energy but can be metabolized as a last resort |
|
|
What is the basal metabolic rate?
|
the metabolic rate resulting from all the essential physiological functions that take place in a resting state
**physical activity adds to the basal energy requirement |
|
|
What does undernourished mean?
|
animals that do not take in enough food to meet their energy requirements
-must metabolize molecules of their own body to provide the energy they need (glycogen, fat, then proteins) -eventually a starving animal must use its own proteins for fuel, impairs body functions and leads to death |
|
|
What does overnourished mean?
|
animals that take in more food than necessary to meet their energy demands
-excess nutrients are stored as increased body mass -glycogen reserves are built up and then additional carbohydrates, proteins and fats are converted to body fat -some species use seasonal overnourishment to survive periods when food is unavailable (in humans, overnourishment is a health hazard) |
|
|
What are the layers of the gut?
|
lumen
mucosa submucosa enteric nervous system peritoneum |
|
|
What is the lumen?
|
the cavity of the gut
|
|
|
What is the mucosa?
|
epithelial cells that have secretory and absorptive functions
|
|
|
What is the submucosa?
|
contains blood and lymph vessels that carry absorbed nutrients to the rest of the body
|
|
|
What is the circular muscle layer?
|
has cells that are oriented around the gut
|
|
|
What is the longitudinal muscle layer?
|
has cells that are orientated along the length of the gut
|
|
|
What is serosa?
|
a fibrous coat that surrounds the gut
|
|
|
What is the peritoneum?
|
a tissue that all abdominal organs are covered and supported by
|
|
|
What breaks down protein, carbohydrates, and fat macromolecules into their simplest monomeric units?
|
hydrolytic enzymes
carbohydrases hydrolyze carbohydrates proteases hyrdrolyze proteins lipases hydrolyze fats nucleases hydrolyze nucleic acids |
|
|
What do the salivary glands secrete?
|
mucus: mucins (a family of large, heavily glucosylated proteins) and inorganic salts suspended in water
amylase: carbohydrase that hydrolyses starch to maltose |
|
|
What are functions of saliva?
|
-lubrication and binding
-solubilizes dry food -oral hygiene -initiates starch digetion |
|
|
How does swallowing happen?
|
-food is chewed and the tongue pushes the bolus of food to the back of the mouth. sensory nerves initiate the swallowing reflex
-soft palate is pulled up as the vocal cords are pulled together to close the larynx -the larynx is pulled up and forward and is covered by the epiglottis. The esophageal sphincter relaxes. The bolus of food enters the esophagus |
|
|
What are the functions of gastric acid?
|
-to kill microorganisms that are taken in with food
-to hydrolyze acid-labile substances -to activate pepsin |
|
|
What is the major enzyme produced by the stomach?
|
the endopeptidase pepsin
-secreted by cells in the gastric glands as a zymogen -newly formed pepsin activates other pepsinogen molecules (autocatalysis) |
|
|
What are parietal and zymogenic cells?
|
parietal cells- acid-secreting cell
zymogenic cells- enzyme-secreting cell |
|
|
What does mucus do?
|
-it is secreted by the stomach's mucous cells and coats the walls of the stomach and protects them from being eroded and disgested by HCl and Pepsin
|
|
|
What causes an ulcer?
|
-when walls of the stomach are directly exposed to HCl and pepsin
-bacterium Helicobacter pylori, not caused by stress |
|
|
What is chyme?
|
mixture of gastric juice and partly digested food
|
|
|
What are peristaltic contractions of the stomach?
|
pushes the chyme toward the bottom end of the stomach and into the beginning of the intestine through the pyloric sphincter
|
|
|
What is the small intestine?
|
-6 meters long
-duodenum-site of most digestion -jejunum/ileum- site of most of the absorption of nutrients. |
|
|
What does the liver do?
|
produces and secretes bile
|
|
|
What does the gallbladder do?
|
stores bile, which aids in digesting lipids(fats)
|
|
|
What does the pancreas do?
|
produces digestive enzymes and biocarbonate solution
|
|
|
How is fat absorbed?
|
-lipases break fats down into diglycerides, monoglycerides and fatty acids which can pass through the plasma membrane of microvilli
-once in the cells they are resynthesized into water soluble "lipoproteins" called chylomicrons. These pass to the lymph vessels in the submucosa -enter the blood through the thoracic ducts |
|
|
What are emulsifiers(surfactants)?
|
bile acids
-have a lipophilic end and lipophobic end -disperse fat droplets into micelles -greatly increases surface area of the fats that are exposed to lipases |
|
|
What are bile acids synthesized from?
|
cholesterol
|
|
|
What is enterohepatic circulation?
|
90% of excreted bile acids are reabsorbed (by active transport in the ileum) and recycled via the liver
10% of bile acids are lost in the feces (major pathway for elimination of cholesterol) |
|
|
What are lipoproteins?
|
-transport fats in the aqueous circulatory system
-consist of a core of fat and cholesterol covered by apolipoproteins that make them water soluble -largest lipoproteins are chylomicrons -lipoproteins are classified according to their density (more fat, lower its density) |
|
|
What is a chylormicron?
|
-largest lipoprotein
-carry triacylglycerol (fat) from the intestines to the liver and adipose tissue |
|
|
What is very low density lipoproteins (VLDL)?
|
carry (newly synthesized) triacylglycerol from the liver to the adipose tissue
|
|
|
What are low density lipoproteins (LDL)?
|
carry cholesterol from the liver cells to cell of the body. (bad cholesterol)
|
|
|
What are high density lipoproteins (HDL)?
|
collects cholesterol from the body's tissue and brings it back to the liver (good cholesterol)
|
|
|
What does the pancreas do (exocrine)?
|
-produces a number of digestive enzymes released as zymogens
-produces a secretion rich in bicarbonate ions which neutralizes the pH of the chyme from the stomach (intestinal enzymes function best at neutral pH) |
|
|
What is trypsinogen?
|
activated in the duodenum by enterokinase which is produced in the cells lining the duodenum
|
|
|
What does trypsin do?
|
active trypsin can activate other trypsinogen molecules by autocatalysis
|
|
|
How are nutrients absorbed?
|
-only the smallest products of digestion can be absorbed through the mucosa (epithelial lining) of the small intestine
-final digestion that produces these absorbable products takes place at the microvilli -membrane bound peptideases on microvilli that cleave peptides into tri- and dipeptides and individual amino acids -intestinal epithelial cells also produce maltase, lactase and sucrase which cleave common disaccharides into monosaccharides |
|
|
What does the large intestine (colon) do?
|
-peristalsis pushes the contents of the small intestine into the large intestine (colon)
-colon absorbs water and ions (producing semisolid feces from indigestible material) -large population of bacteria live in the colon |
|
|
What is the immune system?
|
a set of mechanisms that protect an organism from infection by identifying and killing pathogens
|
|
|
What are pathogens that the immune system must recognize and defeat?
|
-viruses
-bacteria -yeast -parasitic worms -maggots |
|
|
What is the innate immune system?
|
nonspecific defenses
-are inherited mechanisms that protect the body from many different pathogens |
|
|
What is the adaptive immune system?
|
specific defenses
-adaptive mechanisms that protect against specific targets |
|
|
What are the lymphoid tissues?
|
(thymus, bone marrow, spleen, lymph nodes)
-essential parts of the defense system |
|
|
What does blood do?
|
(closed circulatory system)
-suspends red and white blood cells and platelets |
|
|
What are red blood cells?
|
found in the closed circulatory system
|
|
|
What are white blood cells?
|
(and platelets) are found in the closed circulatory system and in the lymphatic system
|
|
|
What is lymph?
|
fluids that accumulate outside of the closed circulatory system in the lymphatic system
|
|
|
What is the lymphatic system?
|
a branching system of tiny capillaries connecting larger vessels
-lymph ducts eventually lead to a large lymph duct that connects a major vein near the heart -sites along lymph vessels are small, roundish lymph nodes |
|
|
What do lymph nodes contain?
|
a variety of white blood cells
-lymph is filtered and white blood cells inspect it for pathogens |
|
|
All blood cells originate from...
|
stem cells in the bone marrow
|
|
|
What are white blood cells?
|
-leukocytes- are important in defense
-clear and have a nucleus and organelles -can leave the circulatory system -can proliferate in response to invading pathogens |
|
|
What are red blood cells?
|
smaller than white blood cells and lose their nuclei before they become functional
|
|
|
What are the two main groups of white blood cells?
|
phagocytes- engulf and digest foreign materials
lymphocytes-specific immunity T cells- migrate from circulation to thymus, where they mature B cells- circulate and also collect in lymph nodes and make antibodies |
|
|
What are the innate systems defenses?
|
-skin- physical barrier to pathogens
-normal flora- bacteria and fungi on surface of the body compete for space and nutrients against pathogens -lysozyme- in tears, nasal mucus, and saliva contains the enzyme that attacks the cell walls of many bacteria -mucus and cilia in the respiratory system trap pathogens and remove them -hydrochloric acid and proteases in stomach- destroys ingested pathogens -bile salts in small intestine- kill some pathogens |
|
|
What is phagocytosis?
|
the process of phagocytes ingesting pathogens
|
|
|
What are neutrophils?
|
-most abundant type of white blood cells (70%)
-attack pathogens in affected tissue -react fast(within hour of insult) -half life of neutrophil in circulation is 4-10 hours |
|
|
What are monocytes?
|
-mature into macrophages
-live longer, consume larger numbers of pathogens than neutrophils -some roam and others are stationary in lymph nodes and lymph tissue |
|
|
What are dendritic cells?
|
highly folded plasma membranes that can capture invading pathogens
|
|
|
What is a respiratory burst (oxidative burst)?
|
neutrophils can execute only one phagocytic event, expending all their glucose reserves
-activation of NADPH oxidase -produces superoxide, hydrogen peroxide and hypochlorous acid -kills all pathogens |
|
|
What is the inflammation response?
|
used in dealing with infection or tissue damage
-mast cells and white blood cells (basophils) release histamine, triggers inflammation -histamine causes capillaries to become leaky, allowing plasma and phagocytes to escape into the tissue -complement proteins and other chemical signals attract phagocytes. neutrophils arrive first, then monocytes (which become macrophages) -macrophages engulf invaders and debris and are responsible for most of the healing (mopping up) -produces cytokines which activates and recruits other immune cells (may signal brain to produce fever) -pus, composed of dead cells and leaked fluid may accumulate |
|
|
What are Toll-like receptors?
|
-key molecules that alert the immune system to the presence of microbial infections
-recognize pathogen associated molecular patters- highly conserved among classes of pathogens and do not occur in hose organism -present in vertebrates and invertebrates (related protein function in plants. one of the most ancient conserved components of the immune system) |
|
|
What are interferons?
|
secreted by cells that are infected with a virus (glycoproteins-160 AA)
-increase resistance of neighboring cells to infections by the same or other virus by increasing expression of protein kinase R (PKR) -PKR is activated by viral dsRNA -PKR activation leads to inhibition of all protein synthesis also inhibits viral replication kills both the virus and host cell if response is active for sufficient time |
|
|
What are four characteristics of the immune system?
|
-specificity
-diversity -distinguishing from nonself -immunological memory |
|
|
What does specificity mean?
|
(reaction to specific antigens)
-antigens are peptides or molecules that are specifically recognized by T cell receptors and antibodies -sites on antigens that the immune system recognizes are the antigenic determinants(epitopes) -each antigen has several different antigenic determinants -the host creates T cells and/or antibodies that are specific to the antigenic determenants |
|
|
What is diversity?
|
human immune system can distinguish and respond to 10 million different antigenic determinants
|
|
|
What is distinguishing from nonself?
|
each normal cell in the body bears a tremendous number of antigenic determinants.
it is crucial that the immune system leaves these alone |
|
|
What is immunological memory?
|
-once exposed to a pathogen the immune system remembers it and mounts future responses much more rapidly
|
|
|
The adaptive immune system has 2 responses against invaders:
|
-humoral immune response
-cellular immune response 2 responses operate in concert and share mechanisms |
|
|
What is the humoral immune response based on?
|
B cells
-produce specific antibodies that recognize antigenic determinants by shape and composition -antibodies recognize pathogens in extracellular spaces (blood, lymph, exocrine secretions) -humor (fluid in latin) |
|
|
What is the cellular immune response?
|
-able to detect antigens that reside within body cells
-destorys virus-infected or mutated cells -T cells -T cells have T cell receptors that can recognize and bind specific antigenic determinants |
|
|
What is clonal selection?
|
the proliferation of a B cell that binds to an antigenic determinant (expanded clone of identical B cells)
-differentiation into "plasma cells" that secrete antibodies and differentiation into "memory cells" |
|
|
An activated lymphocyte (B or T cell) produces two daughter cells:
|
effector B cell- called plasma cells- produce antibodies
memory cells- effector T cells release cytokines- memory cells live longer and retain the ability to divide quickly to produce more effector and more memory cells |
|
|
What is a primary immune response?
|
when the body encounters an antigen for the first time
|
|
|
What is a secondary immune response?
|
when the antigen appears again. response is much more rapid, because of immunological memory
|
|
|
What does vaccination an immunization do?
|
-artificial immunity is acquired by the introduction of antigenic determinants into the body
-inoculation with whole pathogens or with antigenic proteins -initiates a primary immune response that generates memory cells without making the person ill. |
|
|
What are the three principle ways to provoke an immune response but not cause disease with an immunization/vaccination?
|
-attenuation- reducing the toxicity of the antigen molecule or organism (adaption of a virus for growth in nonhuman cells)
-biotechnology- produce recombinant antigenic fragments of pathogens that activate lymphocytes but are harmless by themselves -DNA vaccines- introduce a gene encoding an antigen into the body |
|
|
What is polio?
|
-acute viral infectious disease
-spread via fecal-oral route -majority of polio infections are asymptomatic -1% cases, virus enters the CNS. infects and destroys motor neurons-> paralysis |
|
|
What was the first effective polio vaccine?
|
Salk vaccine/ inactive poliovirus vaccine
-by Jonas Salk (1952) -based on poliovirus grown in a monkey kidney cell line which are then killed with formalin. -injected into skin. |
|
|
What was the oral polio vaccine(OPV)?
|
-Albert Sabin
-live-attenuated vaccine -random mutation in the virus' internal ribosome entry site -replicates efficiently in the gut but is unable to replicate in the nervous system tissue |
|
|
What is self tolerance?
|
-the body is tolerant of its own molecules
-based on clonal deletion -failure to do so is autoimmune disease |
|
|
What is clonal deletion?
|
-eliminates B or T cells from the immune system during their differentiation
-in bone marrow, 90% of all B cells made are removed because they act against self antigens -same in thymus with T cells -apoptosis |
|
|
What are B cells?
|
-basic component of humoral immune system
-for a B cell to differentiate into a plasma cell, it must bind to an antigenic determinant -a Th must also bind the same determinant as it is presented by an antigen presenting cell. -cellular division and differentiation of the B cell is stimulated by a signal from activated Th cell -activated B cells become plasma and memory cells. |
|
|
What are immunoglobulins?
|
antibody molecules are proteins called immunoglobulins
-2 identical light chains and 2 identical heavy chains (disulfide bonds hold chains together) -both the heavy and light chains on each peptide have variable and constant regions -constant regions are similar among the immunoglobulins and determine the class of the antibody -variable regions differ in their amino acid sequences and are responsible for the diversity of antibody specifity -heavy and light chain variable regions align and from binding sites -each has 2 identical antigen-binding sites (bivalent antibody) |
|
|
What are T cell receptors?
|
-genes that code for T cell receptors are similar to those for immunoglobulins
-T cells receptors also have a constant and variable regions -T cell receptors bind only to an antigenic determinant that is displayed on the surface of an antigen-presenting cell. |
|
|
Activated T cells give rise to two types of effector cells:
|
cytotoxic cells Tc- recognize virus infected cells and kill them by causing them to lyse
helper T cells Th- assist both the cellular and humoral immune systems -Activated Th cells proliferate and stimulate both B and Tc cells to divide |
|
|
What is a primary immune response?
|
when the body encounters an antigen for the first time
|
|
|
What is a secondary immune response?
|
when the antigen appears again. response is much more rapid, because of immunological memory
|
|
|
What does vaccination an immunization do?
|
-artificial immunity is acquired by the introduction of antigenic determinants into the body
-inoculation with whole pathogens or with antigenic proteins -initiates a primary immune response that generates memory cells without making the person ill. |
|
|
What are four characteristics of the immune system?
|
-specificity
-diversity -distinguishing from nonself -immunological memory |
|
|
What does specificity mean?
|
(reaction to specific antigens)
-antigens are peptides or molecules that are specifically recognized by T cell receptors and antibodies -sites on antigens that the immune system recognizes are the antigenic determinants(epitopes) -each antigen has several different antigenic determinants -the host creates T cells and/or antibodies that are specific to the antigenic determenants |
|
|
What is diversity?
|
human immune system can distinguish and respond to 10 million different antigenic determinants
|
|
|
What is distinguishing from nonself?
|
each normal cell in the body bears a tremendous number of antigenic determinants.
it is crucial that the immune system leaves these alone |
|
|
What is immunological memory?
|
-once exposed to a pathogen the immune system remembers it and mounts future responses much more rapidly
|
|
|
The adaptive immune system has 2 responses against invaders:
|
-humoral immune response
-cellular immune response 2 responses operate in concert and share mechanisms |
|
|
What is the humoral immune response based on?
|
B cells
-produce specific antibodies that recognize antigenic determinants by shape and composition -antibodies recognize pathogens in extracellular spaces (blood, lymph, exocrine secretions) -humor (fluid in latin) |
|
|
What is the cellular immune response?
|
-able to detect antigens that reside within body cells
-destorys virus-infected or mutated cells -T cells -T cells have T cell receptors that can recognize and bind specific antigenic determinants |
|
|
What is clonal selection?
|
the proliferation of a B cell that binds to an antigenic determinant (expanded clone of identical B cells)
-differentiation into "plasma cells" that secrete antibodies and differentiation into "memory cells" |
|
|
An activated lymphocyte (B or T cell) produces two daughter cells:
|
effector B cell- called plasma cells- produce antibodies
memory cells- effector T cells release cytokines- memory cells live longer and retain the ability to divide quickly to produce more effector and more memory cells |
|
|
What is MHC?
|
-major histocompatibility complex gene products are plasma membrane glycoproteins
-MHC proteins display antigens -MHC I and MHC II |
|
|
What are class I MHC proteins?
|
-present on the surface of every nucleated cell in animals
-when cellular proteins are degraded in the proteasome, an MHC I protein may bind a fragment and travel to the plasma membrane to present it outside on the cell's plasma membrane surface -KILL ME protein -foreign protein fragments from proteosome degradation are bound by class I MHC molecules and carried to the plasma membrane, where Tc cells can check them -if a cell has been infected or is mutated it pay present protein fragments that are not normally found in the body -If a Tc cell binds to the MHC I antigen complex, the Tc cell is activated to proliferate and differentiate (activation phase) |
|
|
What are the phases that Tc cells go through?
|
-activation phase - Tc cell binds to MHC I antigen complex, Tc cell is activated to proliferate and differentiate
-effector phase- Tc cells once again bind to the cell bearing MHC I antigen complex and secrete molecules that lyse the cell (can also bind to a specific target cell receptor Fas) -binding initiates apoptosis in the target (virus infected cell) -this system helps rid the body of virus infected cells and destroy some cancer tumors |
|
|
What are class II MHC proteins?
|
-found mostly on the surface of B cells, macrophages and other "professional" antigen presenting cells
-when an antigen is phagocytosed by a "professional" antigen presenting cell, it is broken down and fragments are presented at the cell surface by class II MHC proteins |
|
|
What are the phases that Th cells go through?
|
-activation- a Th cell containing a specific T cell receptor can bind to an antigen presented by an antigen presenting macrophage (this activates the Th cell: it will proliferate to produce a clonal population of identical Th cells
-effector- antigen of the same sort must also be recognized by a specific IgM receptor on the surface of a B cell B cell ingests and degrades the antigen and presents a piece of processed antigen in a class II MHC protein on its cell surface one of the Th cells created in activation stage recognizes the processed antigen on the surface of the B cell The Th cell releases cytokines, which activate B cell proliferation and differentiation into plasma and memory cells plasma cells secrete antibodies |
