1
Q
What does the digestive system do?
A
brings in food and breaks it down to either get absorbed or eliminated
2
Q
Alimentary canal vs accessory organs?
A
- alimentary canal: continuous muscular tube that propels things; mouth -> anus
- accessory organs: organs that assist the digestive process; like teeth, pancreas, gallbladder
3
Q
What are 6 actions of the digestive system?
A
- ingestion: bringing things into system
- propulsion: moving foods around
- mechanical digestion: turns big pieces into small pieces physically
- chemical digestion: enzymatic breakdown; occurs in the mouth and then stops and starts back up again in the stomach
- absorption: movement of digested products out of lumen of alimentary canal through lining to blood or lymph; usually occurs in SI
- defecation: elimination of waste/feces
4
Q
Is the alimentary canal considered inside or outside the body?
A
outside the body
5
Q
What are 3 types of mechanical digestion?
A
- mastication: chewing
- mixing: mixing food like when tongue moves food or when stomach churns food
- segmentation: when parts of tube constrict and other parts relax
6
Q
What are two types of propulsion?
A
- deglutition: swallowing, voluntary
- peristalsis: wave like smooth muscle contraction, involuntary
7
Q
What are 3 controls of the digestive system?
A
- sensors: mechanical sensors that detect stretch, chemical sensors that detect chemicals
- nerve plexuses: relfexes; long & short
- hormones: long distance chemical messengers
8
Q
Long vs short reflexes?
A
- long: extrinsic; requires CNS activity
- short: intrinsic; does not require CNS activity
9
Q
what are four stimuli for the digestive system?
A
- stretch
- osmolarity
- pH
- presence of specific molecules
10
Q
What are 3 responses to stimuli by the digestive system?
A
- initiate nerve plexus
- activate or inhibit glandular secretions along canal
- activate smooth muscle contraction
11
Q
What is mesentery?
A
double peritoneum membrane that anchors to the back wall of the body and holds abdominal organs in place
12
Q
What are organs called that are in peritoneum? behind peritonuem?
A
- in: peritoneal
- behind: retroperitoneal
13
Q
What are the 4 tunics of the mesentery?
A
- mucosa: most superficial (closest to lumen); one layer of simple columnar epithelial tissue w/ goblet cells & serous glands which secrete mucous, enzymes, and some hormones
- submucosa: where blood vessels and nerves are located; dense irregular connective tissue
- muscularis externa: two layers of muscles (circular & longitudinal) that contraction in two different planes; smooth muscle
- serosa: another name for visceral peritoneum
14
Q
When does it change from adventitia to visceral peritoneum?
A
above diaphragm is adventitia, below is serous & muscularis
15
Q
What are 2 enteric neurons?
A
- submucosal nerve plexus: in submucosa, when stimulated causes glands to start secreting, detect changes of chemistry in lumen or blood
- myenteric nerve plexus: in muscular layer, when activated causes muscular contraction which causes motility, detect stretch
16
Q
What does the parasympathetic vs sympathetic nerve impulses do for digestion?
A
- parasympathetic: activated digestion
- sympathetic: inhibits digestion
17
Q
What are 5 parts of the oral/buccal cavity?
A
- lips & cheeks: boudaries of oral cavity, keep fod sinde
- palate: boundary on roof of mouth separating oral and nasal cavity; contains hard palate at the front where tongue pushes up against to swallow & soft in the back which contains uvula; allows us to breath while eating
- tongue: accessory organ that moves & mixes food w/ saliva and forms food into bolus; contains papillae
- salivary glands: produce saliva which dissolve & moisten food to create a bolus, activates taste buds, clean mouth, and produces enzymes that break down starch
- teeth: accessory organ that functions in mastication
18
Q
What are the 3 salivary glands?
A
- sublingual: beneath tongue, only has mucous cells (secrete mucus)
- submandibular: underneath jaw, has both mucous & serous cells
- parotid: back toward pharynx, has only serous cells (secrete enzymes)
19
Q
What are the 3 types of papillae on the tongue?
A
- filiform: most common, helps us grip food
- fungiform: contains the taste buds
- circumvallate: large papillae at the back of the tongue
20
Q
What is the oral/buccal cavity?
A
entry point and opening of oral cavity; only digestive part that is involved w/ ingestion
21
Q
What 7 things does saliva contain?
A
- water: 97-99%
- electrolytes: contained w/in water
- amylase: produced by serous cells, substrate for starch
- mucin: protein in mucus that makes it slippery
- lysosome: packets of protective enzymes, function in immunity
- IgA: marks things as foreign, function in immunity
- metabolic waste: urea, uric acid
22
Q
What stimulates saliva production?
A
- parasympathetic activity
- chemoreceptors & pressure receptors
23
Q
Why is pH of saliva slightly acidic?
A
prevents bacterial spread
24
Q
What are the two sets of teeth humans have?
A
- primary/deciduous/baby teeth: 20, these fall out and get replaced
- permanent teeth: 32, come in at different times
25
What are the 4 basic types of teeth?
- incisors: 4 front teeth on top & bottom; allows us to bite things off
- cuspid teeth: single tooth on each side of incisors; piercing tooth that allows for biting tings and grabbing hold, indicates meat in diet
- bicuspids/premolars: two on each side of cuspid teeth, for slicing/shearing
- molars: 3 on each side of bicuspid teeth, emerge at different times, for grinding
26
What is the wisdom teeth?
the third molar that usually emerges around 18; usually get these extracted
27
What are the 8 parts of the tooth structure?
- crown: above tooth, visible part
- enamel: hard cover of the crown
- dentine: deep to enamel, surrounds entire tooth
- pulp: contains blood vessel, runs through center of tooth
- root canal: through the bottom of the tooth
- root: below the gum line
- cementum: connective tissue around root that holds the tooth in place
- neck: transition b/w crown and root
28
what type of joint is the teeth?
peg and socket
29
What is the pharynx?
- function is propulsion and contains 3 segments (nasopharynx, oropharynx, laryngopharynx)
30
What is the esophagus?
muscular tube that is collapsed when esophagus is empty and only functions in propulsion
31
What are the 2 physiological sphincters of esophagus?
- upper physiological sphincter: constriction at top that has things move in one direction toward stomach
- gastroesophageal sphincter: constriction before stomach that prevents thins from coming back up into esophagus
32
Why do we have physiological sphincters and not true sphincters in esophagus?
b/c they allows us to vomit if needed
33
What are the steps of deglutition?
1. food compacted into bolus
buccal phase - voluntary
2. tip of tongue is placed against hard palate
3. tongue contracts to force bolus into oropharynx
4. bolus stimulates tactile receptors
pharyngeal-esophageal phase - involuntary
5. tactile receptors stimulate medulla and pons
6. motor impulses sent to muscles
7. peristalsis moves bolus toward stomach
34
What is the stomach?
enlargement of alimentary canal that acts as a storage tank; involves propulsion, mechanical & chemical digestion
35
How does chemical digestion occur in the stomach?
pH stops digestion of salivary amylase and begins protein digestions
36
What are the 6 parts of the stomach?
- fundus: higher than where esophagus enters
- cardia: portion of stomach closest to esophagus
- body: contains 2 curvatures (lesser & greater)
- pylorus: constricted portion at bottom near small intestine
- sphincters: cardiac (not true sphincter?), pyloric (true sphincter that regulates emptying of stomach)
- walls: 3 layers of muscle; organized into rugae which are folds that increase SA & contain gastric pits
37
What type of glands are the gastric pits?
exocrine
38
What is the secretions of the stomach called?
bolus into liquid which is chyme
39
What are the 5 stomach cells?
- goblet cells: embedded in columnar epithelium that produces mucus
- mucous neck cells: deeper in gastric pit, produce slightly more acidic mucus
- parietal cells: middle of gastric pit, secrete HCl & intrinsic factor
- chief cells: deeper in gastric pit near bottom; produce pepsinogen which becomes pepsin after activation from HCl & small amount of lipase
- enteroendocrine cells: G cells; bottom of gastric pits, produce hormones like gastrin
40
What is intrinsic factor?
glycoprotein required for us to absorb B12 (needed to make RBC)
41
What does pepsin & lipase do?
- pepsin: enzyme that breaks down proteins
- lipase: enzyme that breaks down lipids
42
What are the 3 phases of gastric secretion?
- cephalic (reflex) phase: only contains nervous component; innate reflex that becomes conditioned, occurs when stomach activates before food has arrived
- gastric phase: contains nervous & hormonal component; occurs once food arrives in stomach and produces gastric juice
- intestinal phase: intestinal portion of gastric activity that contains two phases
43
what are 3 ways we can produce gastric juice in the gastric phase?
- stretch: stretch receptors send signal to brain and Ach is released which activates production of HCl by parietal cells which stimulates gastric juice
- hormones: presence of proteins or elevated pH activates the enteroendocrine cells to produce gastrin which stimulates parietal cells to release HCI and form gastric juice
- histamine: chemicals released during inflammatory process that get released if we eat contaminated food and stimulates gastric juice
44
What are the two parts of the intestinal phase?
- excitatory phase:
1. small intestine stretches a little bit
2. baroreceptors & chemoreceptors activated
3. signal sent to CNS
4. signal goes to CNS and activates parasympathetic impulses, which cause additional activity in stomach
- inhibitory phase: enterogastric reflex & enterogastrone reflex occurs
45
enterogastric vs enterogastrone reflex?
- enterogastric (neural):
1. material continues to empty from stomach and more stretch on SI
2. receptors send signal to CNS to send sympathetic nervous impulse to shut off stomach
3. sympathetic signal squeezes pyloric sphincter shut
- enterogastrone (hormonal):
1. chyme continues to enter SI, and SI produces enterogastrones (hormone)
2. enterogastrones shut off gastric secretions of stomach
46
what does the mucosal barrier do?
prevents stomach from attacking itself
47
What are 4 parts of the mucosal barrier?
- bicarbonate rich mucus
- tight junctions in mucosal epithelium
- HCl-impermeable plasma membrane in gastric gland cells
- undifferentiated stem cells at junction of gastric pits & gastric glands
48
When does a gastric ulcer occur?
if acid gets through lining of stomach and causes breakdown of mucosal barrier
49
What are two parts of gastric filling?
- receptive relaxation: rugae begin to flatten & stomach begins to stretch in preparation for food to arrive
- adaptive relaxation: when food arrives and stomach adapts by getting bigger around 1 L
50
What controls gastric contraction?
interstitial cells of cajal - autorhythmic cells in longitudinal layer that depolarize abt 3X a min & contractions go from cardia to pylorus
51
What can cause the interstitial cells of cajal to depolarize faster?
nervous impulses or gastrin
52
Where is the highest amount of pressure in the stomach?
at the pyloric sphincter
53
Why does chyme trickle out of stomach?
- chyme is so acidic
- want to digest food
- absorb food efficiently
54
What are the 6 steps of gastric emptying?
1. chyme enters duodenum
2. stretch and chemoreceptors activated
3. enterogastric or enterogastrone reflexes initiated
4. gastric activity reduced
5. pyloric contractions reduced
6. duodenal filling stopped
55
What causes vomiting?
extreme stretch or irritation on stomach which causes 3 layers of muscle to contract along w/ diaphragm & abdominal while pyloric sphincter is shut and everything goes back up
56
What is the major digestive organ of the human body?
small intestine
57
What occurs in the small intestine?
- chemical digestion completed in SI
- all absorption occurs (except water)
- propulsion continues
- no more mechanical digestion
58
What are the 3 subdivisions of the small intestine?
- duodenum: connects to stomach and contains the hepatopancreatic ampulla
- jejunum: middle portion and most variable portion of SI
- ileum: majority of absorption occurs here; connects to cecum of large intestine, contains the ileocecal valves that regulates the emptying of small intestine to large intestine
59
What connects to the hepatopancreatic ampulla?
pancreas, liver, & gallbladder
60
What are 4 structural modification of the small intestine?
- length: allow for increase in SA
- plicae circulares: spiral folds in small intestine that slow movement of chyme
- villi: finger like projections of mucosa
- microvilli: folds in the plasma membrane
61
what is the brush border?
lining of the small intestine responsible for secretions of intestinal juice which helps break down proteins & carbs; production promoted by acidic chyme
62
what is the main digestive function of the liver?
to produce bile - produces all the time
63
What is bile and what is it made of?
an emulsifier which mechanically breaks down fat
made of: water, bile salts (the emulsifier), bile pigments, cholesterol, neutral fats, phospholipids, electrolytes
64
What are the two bile pigments?
- bilirubin: heme from hemoglobin gets converted to this
- urobilinogen: bilirubin broken down to this, responsible for color of feces
65
What is the largest internal organ of body?
liver
66
What are the 5 parts of the liver?
- right lobe
- left lobe
- caudate lobe
- quadrate love
- falciform ligament: suspends liver from diaphragm and separates the L & R lobe
67
What are the two ducts of the liver?
- common hepatic duct: duct that leaves liver and breaks off to cystic duct which goes to gallbladder
- bile ducts: receives bile from liver & gallbladder
68
what are the two functions of the gallbladder?
- stores bile
- concentrates bile: resorbs water out of it
69
When would we need to remove the gallbladder?
when gallbladder removes too much water and bile salts begin to crystallize and plug cystic duct
70
What are the 3 steps of bile storage?
1. hepatopancreatic sphincter closed when not digesting
2. liver continually produces bile
3. bile backs up to cystic duct
71
What are the 4 steps for bile release?
1. fatty chyme entering duodenum stimulates production of cholecystokinin
2. CCK causes parasympathetic impulses to promote gallbladder contraction
3. CCK relaxes hepatopancreatic sphincter
4. CCK stimulates the pancreas
72
What is the digestive function of the pancrease?
produces pancreatic juice
73
Which cells have the exocrine function of pancreas?
acinar cells
74
What 3 things make up pancreatic juice?
- water: mostly water
- enzymes: from acinar cells & break down every category of macromolecule
- bicarbonate: produced from wall of ducts of pancreas & neutralize the acidic chyme
75
What are the 3 protease enzymes produced by the pancreas?
- trypsinogen: activated to trypsin by enterokinase in the SI
- procarboxypeptidase: activated to carboxypeptidase by trypsin in SI
- chymotrpsinogen: activated to chymotrypsin by trypsin in SI
76
Why does the pancreas produce inactive forms of enzymes?
so that the enzymes do not digest the pancreas itself
77
What are 3 other enzymes produced by pancreas?
- amylase: breaks down starch
- lipase: breaks down fat
- nucleases: breaks down nucleic acids
78
What are 3 controls of pancreatic secretion?
- secretin: produced by SI in response to acidic conditions; acts on cells of pancreatic duct to release bicarbonate
- CCK: SI produces this in response to fatty chyme; activates acinar cells to produce enzymes, opens hepatopancreatic ampulla, and causes contractions of gallbladder
- Parasympathetic impulses: cause pancreas to produce both bicarbonate & enzymes
79
What are 3 causes of small intestine emptying?
- gastroileal reflex: long reflex arc from stomach to brain that sends signal to relax ileocecal valve
- gastrin: relaxes the ileocecal valve
- pressure: back pressure; as chyme leaks into cecum it pushes ileocecal valve close
80
Why do we slowly release chyme into large intestine?
- allows us to change pH
- chyme is hypertonic & do not want it to draw water out of large intestine
81
What are two functions of the large intestine?
- absorbs water
- converts chyme to feces
82
What is another name for large intestine?
colon
83
What are the 9 parts of large intestine?
- cecum: entry pathway, contains the vermiform appendix
- ascending colon
- transverse colon
- descending colon
- sigmoid colon
- rectal valves: bending in colon that allows air to pass easily
- rectum: exit
- anus: where we release feces
- sphincters: internal (involuntary) & external (voluntary) around the anus
84
What makes up the feces?
- water
- bacteria
- mucosal cells
- undigested food residues
85
What are the 3 anatomy parts of the large intestine?
- haustra: pucker like pouches
- taenia coli: 3 layers of smooth muscle that make up the haustra
- epiploic appendages: packets of adipose tissue along outside of large intestine
86
What are 3 functions of intestinal bacteria?
- ferment indigestible carbohydrates: forms gas (dimethyl sulfide)
- synthesize B vitamins: aid in neural growth and blood cell production
- synthesize K vitamins: aid in clotting
87
Where do a lot of bacteria accumulate?
near the appendix
88
What are two things that aid in motility of the large intestine?
- Haustral contractions: haustrum contract in response to stretch every 30 minutes
- mass movements: peristaltic waves that push across entire transverse colon and occur 3-4 times a day, prompted by arrival of food in stomach
89
What are the 4 steps of the defecation reflex?
1. mass movements cause stretch
2. stretch triggers parasympathetic stimulation of sigmoid colon and rectum and inhibits anal sphincters (open)
3. external anal sphincter under voluntary control
4. Valsalva's maneuver assists emptying
90
What is valsalva's maneuver?
when we close the glottis and contract our stomach - pushing poop out
91
What type of process is digestion?
catabolic process - large molecules to small molecules
92
What is hydrolysis?
breaking a bond through addition of water
93
What are the 4 classes of carbohydrates in order of breakdown?
- polysaccharides: cellulose, starch, glycogen
- oligosaccharides:n8-10 chains
- disaccharides: sucrose, maltose, lactose
- monosaccharides: glucose, fructose, galactose
94
what are the different digestive enzymes for carbohydrates and their location and substrate?
- salivary amylase - mouth - starch
- pancreatic amylase - pancreas - starch
- dextrinase - brush border - oligo
- glucoamylase - brush border - oligo
- maltase - brush border - maltose
- sucrase - brush border - sucrose
- lactase - brush border - lactose
95
Where are two locations we can get our proteins?
- dietary/extrinsic: from the food we eat
- intrinsic: our own enzymes and mucosal cells
96
What are the 7 protein enzymes and where are they produced?
- pepsin - chief cells
- rennin - babies
- trypsin - pancreas
- chymotrypsin - pancreas
- carboxypeptidase - pancreas/brush border
- aminopeptidase - brush border
- dipeptidase - brush border
97
What enzymes are used and where are they produced for lipid digestion?
lipase - pancreas
98
What enzymes are used and where are they produced for nucleic acid digestion?
- pancreatic nuclease - pancreas
- nucleosidase - brush border
- phosphatase - brush border
99
What are the actions of the nucleic acid enzymes?
- pancreatic nuclease: splits DNA into smaller stranded substrates
- nuclease: breaks nucleotide bones
- phosphatase: breaks phosphate bonds
100
What are two absorption processes?
- active transport into villi capillaries and delivery to liver
- simple diffusion into villi lacteals and delivery to blood by lymph and aided by micelles
101
What is a nutrient and what are their 3 functions?
a substance used by body for a number of different things
- promote growth
- repair
- maintenance
102
What are the 6 nutrients?
- water: in majority of food we eat
- carbohydrates: mostly digested from plants, make ATP
- lipids: animal (saturated) and plants (unsaturated or polyunsaturated), mostly neutral fats
- proteins: plants (incomplete) and animals (complete)
- vitamins: trace nutrient; coenzymes, water soluble are not stored & fat soluble are stored but too much is toxic
- minerals: trace nutrient; found in foods
103
Where can we convert foods groups to another?
liver
104
What is metabolism?
biochemical process of conversion
105
What are tow parts of metabolism?
- anabolism: building it up
- catabolism: breaking it down
106
What are the 3 steps of the metabolic process?
1. chemical digestion and transport of products to cells
2. anabolism of lipids, proteins and glycogen or catabolism of pyruvic acid and acetyl -CoA
3. cellular respiration in mitochondria
107
What is a redox reaction?
- oxidation: addition of oxygen and removal of hydrogen, loss of energy
- reduction: addition of hydrogen, gain energy
108
What are the 3 redox enzymes?
- dehydrogenases: removes hydrogen, catalyzes oxidation
- oxidases: catalyzes oxidation, transfer of oxygen
- coenzymes: hydrogen ion acceptors
109
What are two types of ATP synthesis?
- substrate level phosphorylation: within cytoplasm and direct transfer of phosphate
- oxidative phosphorylation: chemo osmotic process that uses a proton gradient in the mitochondria
110
What are the 4 steps of carbohydrate metabolism?
1. glucose enters cells by facilitated diffusion
2. glucose immediately phosphorylated to glucose-6-phosphate
3. glycolysis continues and results in formation of 2 molecules of pyruvic acid, 2 molecules of NADH and a net gain of 2 molecules of ATP
4. if oxygen is present, oxidative phosphorylation occurs
111
Why do we immediately phosphorylate the glucose in glycolysis?
- shifts gradient to keep more glucose outside
- nonreversible reaction to maintain gradient
112
What are the 4 steps of oxidative phosphorylation?
1. pyruvic acid converted to acetyl-CoA in mitochondria and generates CO2 and NADH
2. acetyl-CoA enters krebs cycle and generates 2 CO2, 2 NADH, 1 ATP, and 1 FADH2
3. reduced krebs cycle coenzymes enter ETC
4. hydrogens used to phosphorylate ADP and generates H2O and 34 ATP
113
what are the 4 steps we do if we have excess glucose?
1. high ATP levels stop glycolysis
2. glucose converted to glycogen - glycogenesis
3. glycogen stored in liver and muscle until energy needed
4. drop in blood glucose stimulated glycogenolysis
114
What is gluconeogenesis?
- insufficient glucose availability prompts conversion of glycerol and amino acids and occurs in liver
115
What are the 3 steps of lipid metabolism?
1. absorbed lipids broken down by plasma enzymes into glycerol and fatty acids
2. glycerol converted to glyceraldehyde phosphate -> pyruvic acid in glycolysis -> krebs
3. fatty acids broke into acetic acid in mitochondria -> fuses w/ CoA to become acetyl CoA -> krebs
116
What do we get the most energy from?
lipids
117
What do we do if we have excess lipids?
- High ATP and glucose levels trigger conversion of glycerol and fatty acids into triglycerides for storage
- lipolysis reverses process
118
What are the two steps of protein metabolism?
1. amino acids deaminated
2. deaminated molecules converted to pyruvic acid or other kreb intermediates
119
What is deamination?
when you remove an amine group from an amino acid
120
What do we do if we have excess proteins?
- high ATP levels cause pyruvic acid formed through deamination to be converted to glucose
121
What can control protein synthesis on ribosomes?
hormones
122
What are nutrient pools?
exchange b/w breakdown and storgae; nutrients can be used immediately, use it for storage, or convert it to building blocks in liver
123
What are two metabolic states?
- absorptive: during or right after meal, anabolic reactions occur
- postabsorptive: b/w meals, catabolism reactions occur
124
What are two hormonal controls of our metabolic states?
- insulin: absorptive; stimulated by high levels of glucose, promotes uptake of glucose and protein synthesis; lowers blood glucose
- glucagon: postabsorptive; stimulated by low levels of glucose, promotes glycogenolysis, lipolysis, gluconeogenesis; increases blood glucose
125
What are two neural controls of metabolic state?
- sympathetic stimulation: stimulated by low blood glucose, targets adipose tissue; during postabsorptive
- epinephrine: sympathetic stimulation of adrenal medulla causes release of this, targets liver, skeletal muscle, and adipose tissue; during postabsorptive
126
What is a liver functions relating to cholesterol?
- it distributes the cholesterol
127
the more cholesterol on the protein the lower the _______
density
128
What are the 6 steps of the liver relating to cholesterol?
1. liver produces VLDL
2. VLDL converted to LDL before leaving liver
3. LDL released to bloodstream
4. lipids taken off carrier protein as delivered to body cells
5. this increases density and LDL becomes HDL
6. HDL goes back to liver to get broken down, re-loaded and re circulated
129
What are two metabolic rates?
- basal metabolic rate: energy we produced just to stay alive
- total metabolic rate: energy that includes BMR and extra activity we do
130
What state must the patient be in when measuring BMR?
post absorptive for at least 12 hrs and relaxed
131
What are two ways to measure metabolic rate?
- colorimeter: place pt in bath & observe temp change to measure energy; direct measurement; disadvantage is not portable and cause stress
- respirometer: deliver air and measure oxygen consumed or carbon dioxide produced; indirect measure; advantage is more portable and can be relaxing
132
What is body temperature?
balance of heat production and heat loss
133
What is the exchange mechanism for heat?
blood
- in core: body temp increases
- in shell: body temp decreases
134
What are 4 ways for heat exchange?
- radiation: temperature moves from high to low, warmer object loses heat to cooler environment
- conduction: increases transfer of heat by coming into contact w/ something
- convection: air movement enhances exchange; wind causes more heat loss
- evaporation: conversion of liquid to gas that takes heat w/ it; sensible heat loss - sweating, related to body temp; insensible heat loss - breathing, not related to body temp
135
What are 5 heat promoting mechanisms?
- vasoconstriction: constriction keeps blood at core and temp goes up
- increase metabolic rate: adrenal medulla releases epinephrine which increases cellular respiration, non shivering thermogenesis
- shivering: involuntary muscle contraction & pilomotor response (raising hairs), shivering thermogenesis
- thyroxine release: done by babies and infants, increase thyroxine production
- behavioral mechanisms: put heavier clothes on, curling yourself up, staying inside, etc.
136
What are 3 heat loss mechanisms?
- vasodilation: send blood to shell and allows for greater heat exchange
- sweating
- behavioral mechanisms: go in shade, lighter clothing, etc.
137
What are the 5 steps of fever?
1. cells release pyrogens
2. pyrogens cause hypothalamus to release prostaglandins
3. prostaglandins reset thermostat
4. vasoconstriction and shivering result
5. body temp increases
BIOL 2230
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