PSIO 202 Exam 3

proteases of the pancreas

trypsin, chymotrypsin, carboxypeptidase, elastase

thyroid hormones

tyrosine ring w/ attached iodines, very lipid soluble, hydrophobic, T3 + T4

smooth muscle of muscularis layer

under voluntary control, inner circular fibers and outer longitudinal fibers, allows motility for mixing and propulsion

congenital hypothyroidism/cretinism

under-active thyroid gland, during development, infancy or early childhood results in dwarfism and severe intellectual disabilities

edema

underactive thyroid gland in adults, can also have low heart rate, muscle weakness, sensitivity to cold, low body temp, weight gain and mental dullness

esophageal stage of swallowing

upper esophageal sphincter relaxes, peristalsis pushes food down: circular fibers contract behind bolus, longitudinal fibers contract in front of bolus to shorten the distance of travel, travel time: 4 to 8 sec for solids, 1 sec for liquids, lower esophageal sphincter relaxes as food approaches

hGH release is regulated by which two hormones?

GHRH and GHIH

low blood glucose levels stimulates release of ____, which stimulates secretion of ___ by somatotrophs, hGH and IGFs ____ the breakdown of liver glycogen into glucose, which enters blood more rapidly, blood glucose levels ____, if ____ too much, the release of GHRH is ____-

GHRH, hGH, speed up, increase, increase, inhibited

sources of electrolytes

GI secretions, ingested foods and liquids

Luteinizing Hormone (LH)

GnRH from hypothalamus stimulates gonadotrophs in anterior pituitary to produce LH

what are the high energy electrons captured by during cellular respiration?

NAD+ and FADH

oxidation reduction in ETC

NADH and FADH2 are oxidized while electrons are reduced

functions of large intestine

SM for mechanical digestion, peristaltic waves (3 to 12 contractions/minute), haustral churning, gastroilial reflex, gastrocolic reflex, defecation reflex, bacteria ferment undigested carbs into CO2 + methane gas, and undigested proteins into simpler substances

gonadotrophs

anterior pituitary cell that secretes Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH)

thyrotrophs

anterior pituitary cell that secretes Thyroid Stimulating Hormone (TSH)

somatotrophs

anterior pituitary cell that secretes human Growth Hormone (hGH)

lactotrophs

anterior pituitary cell that secretes prolactin (PRL)

cephalic phase of digestion

anticipation phase, prepare the mouth and stomach for food, cerebral cortex- sight, smell, taste + thoughts of food stimulate the parasympathetic NS to stimulate salivation (facial and glossopharyngeal) and gastric glands to secrete gastric juice (vagus)

neurosecretory vesicles

antidiuretic hormone and oxytocin made in the hypothalamus are transported here where they are stored until a signal comes to stimulate release

Growth Hormone Releasing Hormone regulates which anterior pituitary hormone?

growth hormone (GH or somatotropin)

what are the primary cells of the liver?

hepatocytes

liver lobule

hepatocytes, hepatic laminae, central vein surrounded by smooth muscle, hepatic sinusoids, portal triad

different target cells may respond to the same ________ differently

hormone

secretin

hormone decreases stomach secretions

oxytocin

hormone of posterior pituitary, produced by cells in paraventricular nucleus of the hypothalamus, target tissues: uterus during labor, mammary glands after delivery

message of endocrine system

hormones

the density of a lipoprotein is determined by

how much protein is present, higher protein= higher density

what is adventitia layer?

consists of areolar CT without the epithelium

Where are the parathyroid glands located?

embedded in the posterior facing side of the thyroid gland

lactic acid role in glycolysis

enables glycolysis to continue in the absence of O2 by regenerating NAD+ in the cytoplasm

goiter

enlarged thryoid gland usually due to lack of iodide in the diet, associated w/ hyperthyroidism, hypothyroidism, or euthyroidism; hypothryoidism: low T3/T4 hormone levels stimulates TSH release by negative feedback, stimulates growth of thyroid gland

absorption of electrolytes

enter epithelial cells by diffusion and secondary active transport, Na and K move by active transport, chloride, iodide and nitrate follow passively, iron, magnesium and phosphate ions use active transport, intestinal Ca2+ absorption requires vitamin D and parathyroid hormone

circulating hormones

enter interstitial fluid and then the blood stream, includes lipid soluble hormones and water soluble hormones

where is the adventitia located?

esophagus

polyphagia

excessive eating

polydipsia

excessive thirst

polyuria

excessive urination

pancreatic juice

exocrine secretion of pancrease, 2L produced per day, colorless liquid (pH 7.1 to 8.2) consisting of: water, salts, sodium bicarbonate, several enzymes

brain prefers ketone bodies when

extreme starvation occurs

how does fructose move into epithelial cells in small intestine?

facilitated diffusion through carrier protein

true/false: hGH is continuously released by the body

false, hGH is released in bursts every few hours

absorption of vitamins

fat soluble vitamins A, D3, E, K travel in micelles and are absorbed by simple diffusion with lipids, water soluble vitamins are absorbed by diffusion, vitamin B12 must combine with intrinsic factor from the stomach parietal cells before it is transported into the cells of the ileum, and absorbed by receptor mediated endocytosis

how does CCK regulate pancreatic secretion?

fats and proteins cause increased digestive enzyme release

do fatty acids or glucose allow for more ATP production?

fatty acids

glucose cannot be formed from

fatty acids

beta oxidation

fatty acids undergo this in mitochondria to produce acetyl coA and lots of ATP

thyroid follicles

follicular cells, parafollicular cells, thryoglobulin (colloid)

brush border enzymes

found on surfaces of microvilli participate in chemical breakdown of carbs, proteins, and nucleosides; pancreatic juice is present in the lumen with chyme, and it contains amylase, proteases, lipase and nucleases, no brush border lipases or nucleases present

water soluble hormones

freely dissolved in body fluids, circulating hormones

stimuli for GHIH by hypothalamus

hyperglycemia, REM sleep, increased fatty acids and decreased amino acids in blood, obesity, low levels of thyroid hormones, high levels of hGH

diabetes mellitus

hyperglycemia, excessive urine production, excessive thirst, excessive eating, type I and II

cushing's syndrome

hypersecretion of glucocorticoids, redistribution of fat to face, spindly arms and legs due to muscle loss, poor wound healing, greater susceptibility to bruising, suppression of immune system, extreme endocrine status, patient is overwhelmingly stressed and muscle loss reflects the mobilization of energy reserves

grave's disease

hyperthyroidism, autoimmune disorder in which unusual antibodies are produced that mimic the action of TSH, stimulating excess production of T3 and T4

stimuli for GHRH by hypothalamus

hypoglycemia, deep sleep, decreased fatty acids and increased amino acids in the blood, increased sympathetic stimulation (due to stress)

where is energy found?

in the bonds btwn atoms

krebs cycle occurs

in the mitochondria

aerobic cellular respiration

in the presence of O2, glucose is completely broken down (oxidized) into CO2, H2) and captured high energy electrons (by NAD+ and FADH), high energy electrons are used by the ETC to pump H+ ions which are used to make ATP via chemiosmosis, the 3 products CO2, ATP and H2) move out of mitochondria into the cytoplasm

hormones are released in response to

internal or external changes

large intestine glands and cells

intestinal gland, absorptive cells, goblet cells, lymphatic nodules, lamina propria, muscularis, submucosa

where do circulatory hormones go after released from endocrine cell?

into venous end of capillary, to the heart, through pulmonary system, and back into systemic circulation

euthyroidism

normal thryoid

is ENS controlled by CNS?

not directly

what lines bile canaliculi?

nothing

haustral churning

occurs in large intestine, relaxed pouches are filled from below by muscular contractions; when full, they contract and move contents to next pouch

ketogenesis

occurs in liver cells, ketone bodies are used by heart muscle and kidney cortex for ATP production

salivary glands

parotid, submandibular and sublingual glands; all have ducts that empty into oral cavity; sight, smell, sounds, memory of food, tongue stimulation increase salivation; fear and anxiety decrease salivation (dry mouth)

hormones

mediator molecules released in one part of the body that regulate activity in other parts of the body

functions of the liver

metabolism of carbs, proteins, lipids; detoxifies the blood by removing or altering drugs + hormones, removes bilirubin, releases bile salts to help digestion by emulsification of lipids, stores fat soluble vitamins, iron, copper and B12, phagocytosis of worn out blood cells + bacteria, plays a role in vitamin D activation pathway

message speed and duration for nervous system

milliseconds to seconds

where does the formation of acetyl co-a occur?

mitochondria

electron transport chain occurs in the

mitochondrial inner membrane

biogenic amines

modified amino acids, catecholamines (TYR modified) : NE, epinephrine, dopamine; serotonin (TRP), melatonin, histamine (HIS)

smooth muscle

modulates luminal pressure/tension, present in sheets, bundles, or sheaths around tissues

functions of saliva

moistens food (swallow), dissolves food (taste), HCO3- buffers acidic foods, protects mouth from infection w/ rinsing action, lysozyme helps destroy bacteria

types of water soluble hormones

peptide and protein hormones, biogenic amines

GI tract organs

mouth, pharynx, esophagus, stomach, small intestine, large intestine, rectum and anus

digestion of proteins

mouth- mechanical, in stomach, HCl denatures proteins, and pepsin breaks proteins into smaller polypeptides, pancreatic enzymes (proteases) in pancreatic juice continue to split peptide bonds btwn amino acids, brush border enzymes aminopeptidase and dipeptidase in small intestine split off amino acids at the amino end of polypeptides (aminopeptidase) and split apart two amino acid chains (dipeptidase)

layers of GI tract

mucosa, submucosa, muscularis, serosa

are kidneys protected by visceral peritoneum?

no

does large intestine have villi?

no

does the posterior pituitary contain cells which make decisions regarding hormone secretion?

no

involuntary stages of swalloing

pharyngeal stage (pharynx to esophagus), esophageal stage (esophagus to stomach)

thromboplastin

phospholipids and tissue factor

lipids can be synthesized to become....

phospholipids of plasma membranes, lipoproteins that transport cholesterol, thromboplastin for blood clotting, myelin sheaths to speed up nerve conduction, cholesterol used to synthesize bile salts and steroid hormones

lactation

process of milk production and ejection

follicular cells

produce "thyroid hormones" T3 and T4

functions of hormones

produce wide-reaching, co-ordinated effects on multiple target tissues, and help to maintain homeostasis, regulate aspects of organ function

Human Growth Hormone (hGH)

produced by somatotrophs in anterior pituitary, target cells include liver, skeletal muscle, cartilage, and bone, causes increase in synthesis of insulin-like growth factors that act locally or enter bloodstream at target cells

nucleases of pancreas

ribonuclease and deoxyribonuclease

bile pathway

right hepatic duct and left hepatic duct into the common hepatic duct from liver, common hepatic duct and cystic duct of gallbladder go into common bile duct, common bile duct and pancreatic duct from pancreas go into duodenum

chemical digestion in the mouth

salivary amylase and lingual lipase

digestion of carbohydrates

salivary amylase in the mouth, mechanical in stomach, pancreatic amylase in pancreatic juice from pancreas, brush border enzymes maltase, sucrase, and lactase in small intestine act on disaccharides (maltose, sucrose, lactose) to produce monosaccharides- fructose, glucose, galactose

structure of smooth muscle cells

sarcoplasmic reticulum is poorly developed relative to skeletal muscle, thick filaments of SM have actin-gripping heads along their entire length, thick and thin filaments are arranged diagonally w/in the cell contraction results in twisting motion

message speed and duration for endocrine system

seconds to minutes, days to weeks

peritoneal cavity

space containing serous fluid

How does the hypothalamus control the anterior pituitary?

special hormones called releasing hormones and inhibiting hormones, hypothalamus releases other hormones directly into circulation through the posterior pituitary

hormone receptors

specific membrane or intracellular proteins that allow hormones to affect target cells

what do the numbers in T1 and T2 represent?

the number of iodine atoms attached to the tyrosine rings

adipocytes

insulin stimulates triglyceride synthesis

4 steps of glucose catabolism

1. glycolysis 2. formation of acetyl coenzyme A 3. krebs cycle 4. electron transport chain

about how many ATP molecules in a cell?

1 billion

triglycerides composed of

1 glycerol and 3 fatty acids

how long is the jejunum?

1 m

chemiosmosis

1. high energy electrons are delivered to ETC complexes, 2. electrons are passed from ETC complex to ETC complex, releasing energy with each transfer that is used to pump H+ ions into the space between the inner and outer membranes of mitochondria, 3. H+ ions are only permitted to move back into matrix thru H+ channels which use the energy of H+ diffusion to power synthesis of ATP from ADP and Pi

absorption of amino acids and dipeptides

1. absorption into epithelial cells of duodenum and jejunum using active transport with Na+ or H+ ions (symporters using secondary active transport), 2. movement out of epithelial cell into blood by facilitated diffusion

absorption of monosaccharides

1. absorption into epithelial cells of small intestine, 2. movement out of epithelial cell into bloodstream by facilitated diffusion

fuel sources for lipogenesis

1. amino acids, glycolysis metabolites, and ketone bodies for fatty acid production from acetyl-CoA, 2. glycolysis metabolites for glycerol production

peptide hormone action

1. binding of hormone to its cell surface receptor activates a specific G protein, which activates adenylate cyclase, 2. activated adenylate cyclase converts ATP to cAMP, 3. cAMP serves as a 2nd messenger to activate protein kinases, 4. activated protein kinases phosphorylate cellular proteins, 5. millions of phosphorylated proteins cause reactions that produce physiological responses, 6. phosphodiesterase inactivates cAMP; the response by target cells to water-soluble hormones is very fast

regulation of digestion phases

1. cephalic phase, 2. gastric phase, 3. intestinal phase

regulation of aldosterone release

1. dehydration, Na+ deficiency or hemorrhage, decrease in blood volume, decrease in BP, increased renin from juxtaglomerular cells of kidney, increased angiotensin I from liver, increased angiotensin II from lungs, increased K+ in ECF of adrenal cortex, vasoconstriction of arterioles, increase in BP, increased aldosterone, increased Na+ and water reabsorption in kidneys + increased secretion of K+ and H+ into urine

negative feedback regulation of calcium levels

1. high levels of Ca2+ in blood stimulates thyroid gland parafollicular cells to release more CT, 2. calcitonin inhibits osteoclasts, thus decreasing blood Ca2+ level, 3. low levels of Ca2+ in blood stimulates parathyroid gland chief cells to release more PTH, 4. PTH promotes resorption of Ca2+ from bone ECM into blood and retards loss of Ca2+ in urine, increasing Ca2+ levels, 5. PTH also stimulates kidneys to release calcitriol, 6. calcitriol stimulates increased absorption of Ca2+ from foods, which increases blood Ca2+ levels

functions of aldosterone

1. increases absorption and reabsorption of Na+ with Cl-, bicarbonate and water following it, 2. promotes excretion of K+ and H+, secretion in kidney

steroid hormone action

1. lipid soluble hormone diffuses into cell, 2. activated receptor-hormone complex alters gene expression (acts as transcription factor), 3. newly formed mRNA directs synthesis of specific proteins on ribosomes, 4. new proteins alter cell's activity; receptors can be found in the cytoplasm or nucleoplasm of target cells, work by changing the level of specific gene expression, relatively slow response by target cells

thyroid hormone regulation

1. low blood levels of T3 and T4 or low metabolic rate stimulate release of 2. TRG, carried by hypophyseal portal veins to anterior pituitary, stimulates release of TSH by thyrotrophs, 3. TSH released into blood stimulates thyroid follicular cells, 4. T3 + T4 released into blood by follicular cells, 5. elevated T3 inhibits release of TRH and TSH (negative feedback)

regulation of bile secretion by enteroendocrine cells (secretin and CCK)

1. parasympathetic impulses along vagus nerve stimulates bile production by liver, 2. fatty acids + amino acids in chyme entering the duodenum stimulate secretion of CCK into blood, 3. CCK causes contraction of gallbladder, 4. secretin enhances flow of bile rich HCO3- from liver

3 ways surface area of small intestine is increased for digestion and absorption

1. plicae circularis, 2. villi, 3. microvilli

absorption of lipids

1. short chain fatty acids are absorbed by simple diffusion, 2. long chain fatty acids and monoglycerides (pdts of lipases) are sequestered w/in tiny micelles after emulsification by bile; will also enter cells by simple diffusion, leaving bile salts behind, bile salts are also reabsorbed and later recycled (into bile) by the liver, fat soluble vitamins (A, K, D3 and E) are able to enter cells w/ lipids, 3. inside epithelial cells fats are rebuilt and coated with protein to form chylomicrons, 4. chylomicrons leave intestinal cells by exocytosis into interstitial fluid where they can only enter lacteals (too big for capillaries), travel in lymphatic system to reach subclavian veins, removed from the blood by the liver and fat tissue

5 types of cells of the anterior pituitary

1. somatotrophs, 2. thyrotrophs, 3. lactotrophs, 4. gonadotrophs, 5. corticotrophs

how long is the duodenum?

10 in

VLDLs

10% protein, 50% triglycerides; form in hepatocytes to transport triglycerides to adipose cells

how many carbons in an acetyl group?

2

how long is the ileum?

2 m

how many net ATP molecules are produced by glycolysis

2 net

during glycolysis, one glucose molecule becomes

2 pyruvic acids

chylomicrons

2% proteins, 85% triglycerides; form in intestinal epithelial cells to transport dietary fats to adipose cells, enter bloodstream through thoracic duct

LDLs

25% protein, 50% cholesterol; bad cholesterol, carry blood cholesterol to body cells

anatomy of small intestine

3 m in total length, 2.5 cm in diameter, large surface area, site of most digestion and most absorption, divided into 3 sections

postabsorptive state metabolism

4 hours after meal when absorption of all nutrients is complete, maintaining normal blood glucose level (70 to 110 mg/dL of blood) is major challenge--> goal is to put glucose back into the blood or use alternative fuel sources

HDLs

40% protein, 20% cholesterol; good cholesterol from liver, carry cholesterol from cells to liver for elimination, associated with low cardiovascular disease risk

absorption of water

9L of fluid enters the GI tract per day, small intestine absorbs 8L, large intestine absorbs last 90% of the last liter, absorption is accomplished by osmosis- thru cell membranes into cells and then from the cells into the capillaries inside the intestinal villi

Corticotropin Releasing Hormone (CRH) regulates which anterior pituitary hormone?

Adrenocorticotropic Hormone (ACTH or Corticotropin), Melanocyte Stimulating Hormone (MSH)

antidiuretic hormone (ADH)

ADH produced by cells in supraoptic nucleus in the hypothalamus in response to signals from osmoreceptors

how is ADH affected by alcohol?

ADH release is inhibited

regulation of ADH

ADH released from posterior pituitary with dehydration of high osmolarity of blood, ADH release inhibited w/ overhydration or low osmolarity of blood

lipids are oxidized to produce

ATP

exchange of energy requires use of

ATP molecules

myenteric plexus of muscularis

Auerbach's plexus, part of ENS with some functions shared with submucosal plexus, provides parasympathetic and sympathetic innervation of circular and longitudinal smooth muscle layers, churning and swallowing

which bonds of glucose have high energy electrons?

C-C, C-H

pyruvic acid breaks down into

CO2, NADH, acetyl coenzyme A

Growth Hormone Inhibiting Hormone (GHIH or Somatostatin) regulates which hormone of the anterior pituitary?

Growth Hormone (GH or somatotropin) and/or Thyroid Stimulating Hormone (TSH)

hypothalamic hormones

Growth Hormone Releasing Hormone (GHRH), Growth Hormone Inhibiting Hormone (GHIH or Somatostatin), Gonadotropin Releasing Hormone (GnRH), Prolactin Releasing Hormone (PRH), Prolactin Inhibiting Hormone (PIH or Dopamine), Corticotropin Releasing Hormone (CRH), Thyrotropin Releasing Hormone (TRH)

ATP synthase in ETC

H+ is forced through the ATP synthase and creates ATP molecule inside the mitochondrial membrane

local hormones examples

IL-2 released from helper T cells stimulates proliferation of helper T cells and activation of cytotoxic T cells (uses both autocrine and paracrine signals), histamine released by mast cells stimulates HCl secretion from parietal cells in stomach

which antibody is ideally suited for secretion in the mucosal lining of our airway and in breast milk?

IgA

Gonadotropin Releasing Hormone (GnRH) regulates which anterior pituitary hormone?

Lutenizing Hormone (LH) and/or Follicle Stimulating Hormone (FSH)

submucosal plexus of the submucosa

Meissner's plexus, part of ENS, receives input from sympathetic (thoracic and lumbar spinal cord) and parasympathetic neurons (vagus nerve and sacral spinal cord), regulates blood vessel diameter, secretion from glands and neurosecretory neurons, and local motility caused by muscularis mucosae

Prolactin Releasing Hormone (PRH) regulates which anterior pituitary hormone?

Prolactin (PRL)

Prolactin Inhibiting Hormone (PIH or dopamine) regulates which anterior pituitary hormone?

Prolactin (PRL), Melanocyte Stimulating Hormone (MSH)

is T3 or T4 more affective?

T3

Thyrotropin Releasing Hormone (TRH) regulates which anterior pituitary hormone?

Thyroid Stimulating Hormone (TSH or Thyrotropin)

what does a cell have to have in order to be considered a target cell for a hormone?

a receptor for that hormone

large intestine function

absorption of electrolytes and some vitamins

cells of small intestine

absorptive cell, goblet cell, enteroendocrine cell, paneth cell

how does secretin regulate pancreatic secretions?

acidity in intestine causes increased sodium bicarbonate release

local hormones

act on neighboring cells (paracrine) or on the same cell that secreted them (autocrine) without first entering the blood stream

message of nervous system

action potentials and neurotransmitters

kinases

add phosphate groups

excess lipids are stored where?

adipose tissue or liver VLDLs

regulation of low blood glucose

alpha cells are stimulated to secrete glucagon which acts on hepatocytes to convert glycogen to glucose, form glucose from lactic acid and certain amino acids, glucose released by hepatocytes raises blood glucose level to normal, if blood glucose continues to rise, hyperglycemia inhibits release of glucagon

proteins are broken down into

amino acids which are transported to the lvier

formation of glycogen from glucose

anabolic reaction

corticotrophs

anterior pituitary cell that secretes Adrenocorticotropic Hormone (ACTH) and Melanocyte Stimulating Hormone (MSH)

serosa

areolar CT, epithelium, simple squamous

digestion of lipids

begins in the mouth with lingual lipase in saliva, continues in stomach with gastric lipase, pancreatic lipase in pancreatic juice continues to split triglycerides into fatty acids and monoglycerides, bile from liver emulsifies lipids to form tiny micelles, no digestion of lipids by the small intestine itself bc no lipase enzymes in membranes of brush border cells

salivary amylase

begins starch digestion in the mouth (ph 6.5-7) but when the bolus hits the acidic gastric juices (pH 2.5) digestion stops, enzyme is destroyed

regulation of high blood glucose

beta cells are stimulated to secrete insulin which acts on body cells to accelerate facilitated diffusion of glucose into cells, speed conversion of glucose to glycogen, increase uptake of amino acids and increase protein synthesis, speed synthesis of fatty acids, slow glycogenolysis, slow gluconeogenesis, if blood glucose continues to fall, hypoglycemia inhibits release of insulin

pathway of bile secretion

bile canaliculi join to form bile ducts at portal triads which form hepatic ducts, L+R hepatic ducts form the common hepatic duct, cystic duct from gallbladder and common hepatic duct join to form common bile duct, common bile duct + main pancreatic duct empty into duodenum

cystic duct

bile is stored here until it is ready to move and be used

intermediate molecule involved in electron transfer of oxidation-reduction

coenzyme NAD+ and FADH

mechanism of action for hormones

bind to cell surface receptors or receptors inside target cells

blood flow through the liver

blood from hepatic arteries and hepatic portal vein mix, the mixed blood flows through the sinusoidal capillaries of the liver then returns to central vein, then hepatic vein, then inferior vena cava, then right atrium of the heart

hypophyseal portal system

blood leaving capillary beds in hypothalamus travels to a capillary bed in anterior pituitary to allow for paracrine secretion of releasing hormones, drained by one or more posterior hypophyseal veins

endocrine and nervous system similarities

both systems act together to control and co-ordinate body activities, both systems use chemical messengers for intercellular communication

lipid soluble hormones

bound to transport proteins for transport in body fluids, circulating hormone

catabolic reactions

break down complex organic compounds, providing energy

glycolysis

break down of glucose to pyruvate/lactate

gastric phase of digestion

breakdown of material; neural: stretch receptors + chemoreceptors increased pH signal bolus entry, vigorous peristalsis + gastric gland secretions, chyme periodically released into duodenum; endocrine: distention + presence of food in stomach cause G cells (enteroendocrines) to secrete gastrin into bloodstream, which increases gastric gland hormone secretions and motility, and causes pyloric sphincter relaxation

second messengers examples

cAMP, calcium ions, cGMP

special features of smooth muscle

capable of sustained contraction w/out fatigue and at very little energy cost, maintains a low level of tension or tone even in the absence of APs, stress relaxation response: stretch causes initial increase in tension, tension decreases within 1-2 mins, allows smooth muscle to change length but maintain ability to contract (important for storage organs)

increase in K+ is a danger to the proper functioning of....

cells

peptide and protein hormones

chains of amino acids, hypothalamic releasing and inhibiting hormones, ADH, oxytocin, hGH, TSH, ACTH

small intestine function

chemical and mechanical breakdown with major absorption

digestion in mouth

chemical and mechanical digestion

CCK

cholecystokinin, decreases stomach emptying

which lipoprotein circulates through lymphatic system?

chylomicrons

major classes of lipoproteins

chylomicrons, very low density, low density, high density lipoproteins

muscularis

circula and longitudinal muscle

krebs cycle

citric acid is produced, CO2 leaves cycle while NADH and H+ are being created

muscosa

closest layer, epithelium, lamina propria, muscularis mucosae

submucosa

connective tissue

loose CT of submucosa

containing blood vessels, glands and lymphatic tissues

intestinal phase of digestion

controlled release of chyme; entry of chyme into duodenum slows gastric activity and increases intestinal activity; neural: distention of duodenum + chemical contents of the chyme activate sympathetic nerves which slow gastric activity; endocrine: distention of duodenum + contents of chyme trigger hormonal release from enteroendocrine cells in the duodenum--> secretin + CCK

transamination

converts one amino acid into another

hypothalamus receives input from...

cortex, thalamus, limbic system and internal organs

Adrenocorticotropic Hormone (ACTH)

corticotropin releasing hormone (CRH) from the hypothalamus stimulates corticotrophs through the bloodstream in the anterior pituitary to release ACTH, ACTH stimulates release of glucocorticoids (mainly cortisol) from adrenal cortex, ACTH release is also stimulated by hypoglycemia, physical trauma, and IL-1

gluconeogenesis is stimulated by

cortisol and glucagon

oxidation reduction reactions

coupled within the body, sometimes use intermediate molecule

glycolysis occurs in the

cytoplasm

fate of amino acids

deaminated to enter krebs cycle, donate amino group to form new amino acids, used to synthesize new proteins throughout the body

protein metabolism liver

deamination, transamination, synthesis of plasma proteins utilized in the clotting mechanism and immune system

oxidation

decrease in the energy content of a molecule: electrons are lost, plus H+

rectum and anus function

defecation

type I diabetes

deficiency of insulin, typically juvenile onset, glucose level high outside cells

oral and pharyngeal stages of swallowing

deglutition starts w/ voluntary stage, food bolus pushed by the tongue into the oropharynx, the involuntary stages begin when sensory nerves in the pharynx that signal the deglutition center in brain stem: breathing stops, soft palate + uvula rise closing off nasopharynx, vocal chords adduct, larynx rises, epiglottis covers the larynx

steroid hormones

derived from cholesterol, chemical groups attached to core of structure makes it unique, cortisol, testosterone, estrogens, progesterone, aldosterone

absorption of amino acids into body cells is stimulated by

insulin-like growth factors + insulin

how does a hormone cause one type of response in one target cell but then also cause a completely different in another target cell?

different types of receptors generate different second messengers

unitary smooth muscle cells line the

digestive tract, gall bladder, urinary bladder

endocrine regulation of stomach function

distention and presence of food in stomach cause G cells to secrete Gastrin into the bloodstream, gastrin increases gastric gland secretions and motility, and causes pyloric sphincter relaxation

posterior pituitary gland

does not synthesize hormones, consists of axon terminals from 2 groups of hypothalamic neurons which release two peptide hormones that enter capillaries- antidiuretic hormone(vasopressin), and oxytocin (OT)

sections of small intestine

duodenum, jejunum, ileum

exophthalmos

edema behind eyes due to hyperthyroidism

oxytocin regulation after delivery

effect on mammary glands: suckling + hearing baby's cry stimulates oxytocin release, oxytocin causes muscle contraction + milk ejection; milk production is stimulated by Prolactin, prolactin and oxytocin work together in lactation, oxytocin controls ejection

what are spaces btwn hepatocytes filled with?

either blood filled sinusoids or bile canaliculi

what powers the formation of ATP?

electrochemical gradient of H+

skeletal muscle of muscularis layer

in mouth, pharynx, upper esophagus, and anus under voluntary control, controls deglutition and defecation

mechanical digestion in the stomach

gentle mixing waves occur in the stomach to mix the bolus of food with gastric juice (enzymes, acid, water) and turn it into chyme (a thin liquid), more vigorous waves traveling from the body of stomach to the pyloric region move the chyme along, intense waves near the pylorus lead to opening of the pyloric sphincter- squirting 1-2 teaspoons into the duodenum with each wave

hormones are released from

glands

glycogenolysis is stimulated by

glucagon and epinephrine

carbohydrate metabolism liver

gluconeogenesis, glycogenesis, glycogenolysis

postabsorptive state summary

glucose enters blood from the liver- glycogenolysis, gluconeogenesis (glycerol from adipose tissue, amino acids and lactic acid from muscle), alternative fuel sources are fatty acids from adipose fed into krebs as acetyl coA for most cells, oxidation of ketone bodies by heart and kidney, most tissues switch to utilizing fatty acids, except brain still prefers glucose

excess amino acids can be converted into

glucose or triglycerides

is glycogenesis or glycogenolysis favored after a meal?

glycogenesis because insulin rises

Follicle Stimulating Hormone (FSH)

gonadotropin releasing hormone (GnRH) from hypothalamus stimulates gonadotrophs in anterior pituitary to produce FSH (also LH)

addison's disease

hyposecretion of glucocorticoids and aldosterone, hypoglycemia, muscle weakness, low BP, dehydration due to decreased Na+ in blood, mimics skin darkening effects of MSH, potential cardiac arrest

control center for feedback loops

hypothalamus

what is considered the headquarters of the ANS?

hypothalamus

which center provides a link between the external and internal environment and the endocrine system?

hypothalamus

control almost all aspects of growth, development, metabolism, and homeostasis

hypothalamus and pituitary gland

hGH: hypothalamic control of release, target tissue and downstream effects

hypothalamus inhibiting hormone GHIH, anterior pituitary cell: somatotrophs, tropic hormone: hGH, target tissues: liver, muscle, cartilage, bone, IGFs

hypothalamus control of anterior pituitary

hypothalamus makes decisions based on sensory inputs, hypothalamus may send motor impulses to various tissue effectors, may make use of endocrine system as an effector by secreting releasing/inhibiting hormones which act on target cells in anterior pituitary, in response, the 5 types of anterior pituitary cells release more or less of the 7 tropic hormones into blood for circulation throughout the body

Prolactin (PRL)

hypothalamus regulates lactotroph cells by secreting PRH and PIH (dopamine), lactotrophs in anterior pituitary produce prolactin, prolactin causes milk production under right conditions, suckling reduces levels of hypothalamic inhibition and prolactin levels rise along w milk production

Thyroid Stimulating Hormone (TSH)

hypothalamus regulates thyrotrophs (via TRH) in anterior pituitary to produce TSH (thyrotropin), TSH stimulates the synthesis and secretion of T3 and T4, metabolic rate stimulated

Regulation of ACTH release

hypothalamus releases CRH, CRH stimulates release of ACTH, ACTH stimulates release of cortisol, cortisol inhibits release of CRH and ACTH

Regulation of Thyrotropin (TSH) release

hypothalamus releases thyrotropin releasing hormone (TRH), TRH causes release of thyroid stimulating hormone (TSH) from anterior pituitary cells, thyroid gland cells activated to secrete more T3 and T4

hGH: hypothalamic control of release, target tissues, and downstream effects

hypothalamus releasing hormone: GHRH, anterior pituitary cell: somatotrophs, tropic hormone: hGH, hGH target tissues: liver, muscle, cartilage, bone, IGFs produced, causes growth of body cells, protein synthesis, tissue repair, lipolysis, elevation of blood glucose concentration

organs/tissues with endocrine cells (not considered endocrine glands)

hypothalamus, thymus, pancreas, ovaries, testes, kidneys, skin, liver, stomach, heart, adipose tissue

where does small intestine end?

ileocecal sphincter valve (connects to large intestine)

how are hepatocytes arranged?

in grids in lobules with spaces in between

deamination of amino acids

in liver, removes NH2 group from amino acids so we can use what is left as an energy source, converts resulting toxic ammonia into urea for excretion by the kidney

glycogenesis

in liver- adds excess glucose into glycogen polymer for storage

glycogenolysis

in liver- breaks off glucose from glycogen polymer in case of need

gluconeogenesis

in liver- turns certain amino acids into glucose, turns the glycerol portion of fats into glucose, to increase blood glucose

hepatocytes

insulin stimulates glycogen synthesis

cortisol

in zona fasciculata of adrenal gland, major human glucocorticoid

diabetes insipidus

inability of the kidneys to conserve water, excessive urination, due to lack of ADH

actions of thyroid hormones

increase basal metabolic rate by stimulating cellular use of O2 to produce ATP-- increased cellular catabolism of glucose, fatty acids, and triglycerides; increase synthesis of Na/K ATPase-- more ATP used to pump ions, ATP use produces heat which raises body temp., calorigenic effect; enhance some actions of sympathetic NS by up-regulating beta receptors-- increased heart rate, contractility and blood pressure; stimulate growth in conjunction w/ hGH and insulin during development

insulin-like growth factors (IGFs)

increase cell growth and cell division by increasing uptake of amino acids and synthesis of proteins, stimulate lipolysis in adipose tissue (released fatty acids are used for ATP production in most body cells), decrease glucose use by most body cells so blood glucose levels remain high enough to supply the brain

functions of villi and microvilli

increase of SA for absorption, brush border enzymes, cell division within intestinal glands produces new cells that move up to replace old cells that have been lost

reduction

increase of energy content of a molecule: electrons gained, plus H+

deglutition

initiation of swallowing

glycogenesis is stimulated by

insulin

type II diabetes

insulin insensitivity, typically adult onset, wonky insulin receptors

high levels of glucose in blood normally causes

insulin release by the endocrine pancreas, binding of insulin hormone to target cells, increased uptake of glucose by target cells

formation of thyroid hormones

iodide trapping by follicular cells, synthesis of thyroglobulin (TGB), release of TGB into colloid, iodination of tyrosine in colloid, formation of T3 and T4 by combining T1 and T2 together, uptake + digestion of TGB by follicle cells, secretion of T3 and T4 into blood, binds to thyroxine binding globulin (TBG)

aspects of organ function regulated by hormones

ion and nutrient levels in ECF and blood, metabolic pathways, biological clock, contraction of cardiac + smooth muscle, glandular secretion, some immune functions, growth and development, reproduction

enterogastric reflex

is stimulated by the presence of chyme in the duodenum, decreases gastric peristalsis + decreases gastric gland secretions

if a heart transplant patient receives prednisone to help prevent rejection of the transplanted tissues, will ACTH and CRH be high or low?

low due to negative feedback suppression of ACTH and CRH release

how are lipids transported through blood?

lipoproteins, protein portion can dissolve in water/blood

major producers of IGFS

liver

autocrine cell

local hormones, releases autocrine hormones to autocrine receptors on the same cell

paracrine cell

local hormones, releases paracrine hormones that bind to a paracrine receptor on a nearby target cell

gastro-esophageal reflux disease (GERD)

lower sphincter fails to open- distension of esophagus feels like chest pain or heart attack; lower esophageal sphincter fails to close- stomach acids enter esophagus + cause heartburn, worsened by a weak sphincter, particularly bad when laying down after large meal, smoking and alcohol make the sphincter relax, worsening the situation

kupffer cells

macrophages in the liver, phagocytize microbes and foreign matter

aldosterone

major human mineralocorticoid

mechanical digestion in the mouth

mastication (chewing), breaks food into pieces, mixes with saliva so that it forms a moist bolus

unitary smooth muscle cells

may not have direct contact w/ any motor neuron, autorhythmic- adjacent cells connect via gap junctions, cell membranes adhere to one another-- transmission of force, slowly synchronized "graded" contraction, entire sheet of muscle contracts- as a functional syncytium, desmosomes

stomach function

mechanical and chemical breakdown with some absorption

mouth function

mechanical and chemical breakdown, deglutition (swallowing)

enteropeptidase

on brush border cells, activates trypsinogen to trypsin, which then activates chymotrypsinogen, procarboxypeptidase, proelasease

lipoprotein lipase

on endothelial cell apical membranes, breaks down fats on VLDLs and chylomicrons

each anterior pituitary cell type has unique receptors for the correct releasing factor located where?

on its plasma membrane

how many target cell types are there for one hormone?

one or more types of target cells

parathyroid glands secrete

parathyroid hormone

voluntary stage of swallowing

oral cavity to oropharynx

hyperthyroidism

overacitve thyroid, symptoms: weight loss, nervousness, tremor, increased heart rate/blood pressure, exophthalamus, high body temp, sweating

the final acceptor of transferred electrons in the electron transport chain is...

oxygen

the positive feedback of childbirth is stimulated by which hormone?

oxytocin

alpha cell

pancreas islet cell that secretes glucagon

enzymes secreted by the pancreas

pancreatic amylase, trypsin, chymotrypsin, carboxypeptidase, elastase, pancreatic lipase, ribonuclease, deoxyribonuclease

hepatopancreatic ampulla

pancreatic duct and the common bile duct unite to form this

beta cell

pancreatic islet cell that secretes insulin

delta cell

pancreatic islet cell that secretes somatostatin

pancreas

pancreatic islets, alpha cells, beta cells, delta cells, F cell

major exocrine secretions of pancreas

pancreatic juice, enzymes

endocrine glands

pituitary, thyroid, parathyroid, adrenal, pineal

what makes up a portal triad?

portal vein, hepatic artery, bile duct

which portion of the pituitary gland is made of neural tissue?

posterior pituitary

neurohypophysis is another name for the

posterior pituitary gland

dehydroepiandrosterone (DHEA)

precursor to testosterone; produced in the adrenal cortex (zona reticularis)

actions of ADH

prevents diuresis- decreases urine production by stimulating the kidneys to return more water back to the blood, prevents water loss in sweat glands, causes constriction of arterioles (vasopressin)

innervation and stimulation of smooth muscle

primarily under control of ANS- "involuntary", diffuse branching of nerve fibers, transmitters include ACh (parasympathetic) and NE (sympathetic), membrane potential 50-60 mV

chemical digestion in the stomach

protein digestion begins in the stomach- HCl denatures (unfolds) protein molecules, HCl activates pepsinogen into pepsin- an enzyme that breaks peptide bonds btwn certain amino acids, fat digestion continues- gastric lipase splits the triglycerides in milk fat, although this is more effective at pH 5-6 (infant stomach), HCl kills microbes in food, mucus cells secrete mucus to protect the stomach walls from being digested

glucocorticoids

raise BP by increasing sensitivity of blood vessels to other hormones which cause vasoconstriction (permissive effects), anti-inflammatory + immunosuppressive by reducing release of histamine from mast cells, decreasing capillary permeability, depressing phagocytosis, inhibiting white blood cells

chromaffin cells

receive direct innervation from sympathetic nervous system, develop from same tissue as postganglionic sympathetic neurons, acts as a modified sympathetic ganglion

function of cortisol

regulation of metabolism during stress, increase rate of protein catabolism and lipolysis, promote gluconeogenesis, provide resistance to stress by making nutrients available

how does hypothalamus control posterior pituitary?

releases hormones directly into circulation through the posterior pituitary

phosphatases

remove phosphate groups

absorptive state

represents the time after a meal when nutrients enter the blood and need to be stored, hepatic portal system is used for absorption of glucose and amino acids, the liver acts on these first, lacteals are used for absorption of dietary fats which are transported as lipoproteins (chylomicrons) through the lymphatic system before reaching general circulation

structures of posterior pituitary

resembles neural tissue with glial cells, nerve fibers, nerve endings, and neurosecretory vesicles

aldosteronism

results from hypersecretion of mineralocorticoids, results in high BP caused by retention of Na+ and the resultant increase in plasma volume

exocrine glands

secrete products into ducts or lumens or to the outer surface of the body, not part of the endocrine system, ex. sweat

endocrine glands definition

secrete products into interstitial fluid which diffuse into blood

proteases

secreted as inactive precursors

parathyroid hormone (PTH)

secreted by chief cells of parathyroid gland, raises blood Ca2+ levels by stimulating osteoclasts, encourages Ca2+ retention by kidneys and absorption of Ca2+ in diet, inhibits reabsorption of phosphate (bone), promotes formation of calcitriol (active vitamin D) by kidney which increases absorption of Ca2+ and Mg2+ by the cells that line the GI tract

Melanocyte Stimulating Hormone (MSH)

secreted by corticotrophs in anterior pituitary, excessive levels of CRH from the hypothalamus increases MSH release from the anterior pituitary, PIH inhibits MSH release, function unclear in humans but high levels increase skin pigmentation

lingual lipase

secreted by glands in tongue and begins breakdown of triglycerides (lipids) into fatty acids and glycerol, replaced by gastric enzyme

calcitonin

secreted by parafollicular cells of thyroid gland, lowers blood Ca2+ levels by inhibiting osteoclasts

hormone release by the hypothalamus and pituitary gland

secreted in first capillary bed, travel through portal veins and exit and influence cells in anterior pituitary in 2nd capillary bed

which hormones regulate pancreatic secretions?

secretin and CCK

in females, LH stimulates

secretion of estrogen and progesterone, ovulation, formation of corpus lutem

in males, LH stimulates

secretion of testosterone, release of GnRH is inhibited by testosterone, if male receives testosterone injections, gonadotrophs would decrease in number/activity

electron transport chain

series of integral membrane protein complexes in the inner mitochondrial membrane of mitochondria, ETC complexes are capable of oxidation/reduction,

what is the serosa layer

serous membrane also called the visceral peritoneum, secretes serous fluid, consists of areolar CT covered with simple squamous epithelium

regulation of glucocorticoid release

some stimulus disrupts homeostasis by decreasing glucocorticoid level in blood, neurosecretory cells in hypothalamus are receptors, CRH is increased and cortisol is decreased, corticotrophs in anterior pituitary cause increased ACTH which causes cells in zona fasciculata in adrenal cortex to secrete glucocorticoids, causes increased glucocorticoids in blood

what lines bile ducts?

simple cuboidal epithelium

monoglyceride

single fatty acid and glycerol

type of smooth muscle cells in digestive system

single/unitary (visceral)

enteroendocrine cells

small intestine, S cells which make secretin, CCK cells which make cholecystokinin and K cells which release GIP

absorptive cell

small intestine, absorbs nutrients

paneth cell

small intestine, secretes lysozyme and is capable of phagocytosis

goblet cell

small intestine, secretes mucus

length tension relationship in smooth muscle

smooth muscles operate over a wider range of resting lengths, generally broader length-tension relationship in smooth muscle compared to skeletal muscle

how do glucose and galactose move into epithelial cells of small intestine?

sodium symporter (secondary active transport)

lipoproteins

spheres containing hundreds of molecules, surrounded by a coat of phospholipid

types of lipid soluble hormones

steroid hormones, thyroid hormones

in females, FSH

stimulates secretion of estrogen, initiates the formation of follicles w/in the ovary

in males, FSH

stimulates sperm production in testes

oxytocin regulation during labor

stimulation of uterus by baby's head causes stretch of cervix, oxytocin release from posterior pituitary, uterine smooth muscle contracts, as the baby's head is pushed into the cervix oxytocin release increases, muscle contraction occurs which pushes the baby further and elicits even more oxytocin release, positive feedback loop ceases when baby is born

where is serosa layer found?

stomach and intesstines

parietal cell

stomach cell, secretes HCl acid and intrinsic factor for B12)

chief cell

stomach cell, secretes pepsinogen and gastric lipase

G cell

stomach cell, secretes the hormone gastrin, monitors fluid in stomach and secretes hormones into blood

stomach anatomy

stomach filling triggers secretions and motility, stomach empties slowly into the duodenum as small squirts of chyme leave through the pyloric sphincter

mucus neck cell

stomach, secretes mucus

surface mucous cell

stomach, secretes mucus

absorptive state summary

storage of excess fuels occurs in hepatocytes, adipocytes, skeletal muscle; most glucose entering liver cells is converted to glycogen (10%) or triglycerides (40%), dietary lipids are stored in adipose tissue, amino acids are deaminated to enter krebs cycle or are converted to glucose or fatty acids, amino acids that are not taken up by hepatocytes are used by other cells for synthesis of proteins

excess amino acids cannot be

stored

epithelium of mucosa

stratified squamous in mouth, esophagus and anus; simple columnar in the rest of GI tract- secretes enzymes and absorbs nutrients, specialized goblet cells secrete mucous onto cell surfaces, enteroendocrine cells secrete hormones controlling organ function

neural regulation of stomach function

stretch receptors + chemoreceptors (pH) signal bolus entry, and this leads to an increase in parasympathetic nerve impulses to effectors in the stomach, vigorous peristalsis + gastric gland secretions result, chyme periodically released into the duodenum until return to homeostasis

cell types of the stomach

surface mucous cell, mucous neck cell, parietal cell, chief cell, G cell

pharynx and esophagus function

swallowing and avoiding airway

blood vessel diameter is controlled by which nervous system division and which endocrine hormone?

sympathetic division, angiotensin II

how do cells respond to hormones?

synthesis of new molecules, change in membrane permeability, altered rates of reaction

anabolic reactions

synthesize complex molecules from small molecules, requiring energy

lipid metabolism in liver

synthesizes cholesterol, phospholipids, and lipoproteins (LDL and HDL- used to transport fatty acids and cholesterol in the blood stream); stores some fat, uses fatty acids + glucose for ATP production, exports fatty acid conversion pdts called ketone bodies for use by other tissues

lamina propria of mucosa

thin layer of CT, contains blood vessels and lymphatic tissue

muscularis mucosae of mucosa

thin layer of smooth muscle causes folds to form in mucosal layer, drives local movements to increase absorption by exposing ingested material to absorptive surfaces

lactose intolerance

those w/out lactase will have bacteria ferment lactose, and the result will be gas and diarrhea

lipolysis

triglycerides are broken down into glycerol and fatty acids within liver or adipose cells in the presence of epinephrine, norepinephrine, cortisol; fatty acids cannot pass blood brain barrier

lipogenesis

triglycerides are synthesized from amino acids or glucose within the liver or adipose cells in the presence of insulin

where are circulatory hormones released from endocrine cell?

venous end of capillary

the peritoneum

visceral peritoneum covers organs, parietal peritoneum lines the walls of body cavity

external anal sphincter is voluntary or involuntary

voluntarily controlled

stages of swallowing

voluntary stage, involuntary stage

second messengers

water soluble peptide hormones bind to cell surface receptors and produce intracellular second messenger, hormones may increase or decrease the level of second messenger, the same hormone may use different second messengers in different target cells, second messengers initiate a cascade of biochemical reactions, often involving phosphorylation or dephosphorylation within target cells

composition of saliva

water, HCO3-, enzymes

absorption of nutrients by the stomach

water, electrolytes, some drugs (aspirin) + alcohol, fat content in the stomach slows the passage of alcohol to the intestine, where absorption is more rapid, alcohol is absorbed more slowly if taken with a meal

defecation reflex

when rectum fills, sensory input from stretch receptors in rectum is sent to sacral spinal cord, control center in sacral spinal cord region may activate visceral motor (parasympathetic pre-ganglionic) neuron output to rectum and anus, parasympathetic nerves contract muscles of rectum and relax internal anal sphincter to expel feces

gastrocolic reflex

when stomach fills, a strong peristaltic wave moves contents of transverse colon into rectum

gastroilial reflex

when stomach is full, gastrin hormone relaxes ileocecal sphincter so small intestine will empty into large intestine

adrenal medulla

where chromaffin cells secrete 20% NE (as a long lasting hormone) and 80% epinephrine, responds to sympathomimetic nervous system signals- mimic sympathetic NS, cause fight-flight behavior

zona reticularis

where target cells for ACTH secrete androgens

zona fasciculata

where target cells for ACTH secrete glucocorticoids, mainly cortisol

zona glomerulosa

where target cells for angiotensin II secrete mineralocorticoids, mainly aldosterone

are lipids nonpolar?

yes

can organs have both exocrine and endocrine portions?

yes, but only the endocrine portion is part of the endocrine system

subdivisions of adrenal glands

zona glomerulosa, zona fasciculata, zona reticularis, adrenal medulla

androgens

zona reticularis, dehyroepiandrosterone (DHEA), insignificant in males, may contribute to sex drive in females, converted to a form of estrogen in postmenopausal women