phys final 🧬

• hormone overview

  • chemical messengers carried in the blood
  • reaches all cells
  • only affects cells with receptors
  • determines effect
  • location
  • cell membrane
  • intracellular
  • lipid soluble
• hormones in the hypothalamus

  • releases and inhibits hormones for the anterior pituitary
  • synthesis of posterior pituitary hormones
• posterior pituitary

  • synthesis of hormone in the nerve cell body --> travels down axon to posterior pituitary --> released in blood
  • vasopression (adh) and oxytocin
• anterior pituitary

  • transfers via portal system
  • direct route
  • capillary --> vein --> capillary
  • not diluted by circulation

  hormones

  • stimulates/ inhibits a 3rd hormone
  • directly affects tissues
  • prolactin and growth hormone
• cascade: hypothalamus - anterior pituitary - cellular effects

  • prh --> pih = prolactin --> reproduction
  • ghrh --> ghih = growth hormone --> metabolism
• cascade: hypothalamus - anterior pituitary - peripheral gland (3rd hormone)

  • trh --> tsh = thyroid
  • crh --> actsh = cortisol
  • gnrh --> fsh, lh = progesterone, estrogen, testosterone
• growth hormone - energy and growth

  • stimulates bone growth in young
  • amplified by sex hormones (puberty)

  disorders

  • giantism (high growth hormone while a child) = big
  • dwarfism (low growth hormone while a child) = small
  • acromegaly (high growth hormone while an adult) = bones thicken because the epiphyseal plates are closed
• peripheral hormone disorders

  • classified by location
  • 1*: disfunction of endocrine gland: secretes too much or too little hormone
  • 2*: disfunction of hypothalamus or pituitary gland
  • too much = too high level of final hormone
  • too little = too low level of final hormone
  • endocrine body responds normally to an abnormal level

  diagnosis: blood level

  • stimulating and peripheral hormone (too high or low - compare with expected value)
• common peripheral hormone disorders

  • cortisol - stress hormone
  • adrenal gland cortex
  • cushing's = too high
  • addison's = too low
  • thyroid hormone - metabolism
  • thyroid gland
  • hyperthyroidism = too much
  • hypothyroidism = too little
  • gonads - reproduction
  • high or low sex hormones
  • progesterone, estrogen, testosterone
• negative feedback to determine the location of the hormone imbalance
• pancreatic hormones - insulin

  • beta cells - islets of Langerhans
  • anabolic - storage
  • effects - binds to a receptor
  • increase glucose transporters
  • increase glucose to cells
  • decrease blood glucose
  • fat and muscle
  • increase amino acid transporters
  • increase glycogen, protein, fat synthesis
• insulin regulation by negative feedback

  • sensor: beta cells
  • increase glucose = increase insulin
  • decrease glucose = decrease insulin
  • plasma amino acid concentration
  • increase aa = increase insulin
  • decrease aa = decrease insulin
  • feed forward
  • intestinal hormone
  • parasympathetic = increase insulin
  • sympathetic = decrease insulin
• glucagon

  • alpha cells
  • catabolic - take out of storage
  • effects: increase blood glucose
  • liver
  • increase synthesis of glucose
  • increase breakdown of glycogen
  • adipose tissue
  • breakdown fat --> liver
  • negative feedback
  • increase plasma glucose = decrease glucagon
  • decrease plasma glucose = increase glucagon
• diabetes

  • IDDM: insulin dependent diabetes mellitus - type 1
  • beta cells are destroyed by the immune system
  • no insulin, needs injection
  • somewhat genetic
  • NIDDM: not insulin dependent diabetes mellitus - type 2
  • insulin levels can be high, low, normal
  • insulin resistance: cell response to insulin is reduced or absent
  • highly genetic
  • obesity and sedentary lifestyles
• calcium balance

  • total body ca
  • bones - 99%
  • in cells - intracellular
  • plasma and interstitial space
  • changes in ca total body
  • input or output
  • increase absorption from intestines = increase ca total body
  • loss in the urine = decrease ca total body
• correct low plasma ca

  • increase parathyroid (PTH)
  • ca bone --> plasma
  • activate vitamin d (kidney)
  • increase ca reabsorption of kidney tubules

  high plasma ca = inhibit parathyroid

  low plasma ca = stimulate parathyroid

  increase vitamin d

  • increase ca absorption in intestines
  • increase ca reabsorption in kidney
• correct high plasma ca

  • increase calcitonin (thyroid gland c cell)
  • increase ca to bone
  • decrease ca reabsorption to kidney tubule

  high plasma ca = stimulate calcitonin

  low plasma ca = inhibit calcitonin
• digestion structure

  • lumen: hollow center
  • inner layers: mucous membrane
  • absorptive cells
  • exocrine cells
  • secrete into lumen
  • enzymes and mucus
  • endocrine cells
  • release hormones/chemicals into the blood
  • other layers
  • connective tissue and muscle
  • nervous control
  • network of nerves within the gut wall - enteric nervous system
• digestion: anatomy

  • mouth: salivatory glands
  • pharynx
  • esophagus
  • stomach
  • small intestine (8-10ft)
  • duodenum (1 ft)
  • jejunum (3-4ft)
  • illeum (4-5ft)
  • large intestine
  • rectum
• digestion: overview

  • eat
  • mechanical breakup
  • digestion (small intestine)
  • enzyme breakdown
  • bile from liver
  • absorption (small intestine)
  • lumen --> blood
  • elimination and storage
  • colon
• detailed structure of digestion

  max diffusion - absorption

  • large surface area
  • villi, microvilli
  • short distance
  • capillaries, lymph beneath mucosa
  • path of nutrient absorption
  • amino acids and sugars
  • intestinal capillary collected into hepatic portal (cap-vein-cap)
  • intestine --> liver (process nutrients) --> normal circulation
  • colon cancer can spread to liver
  • fat enters lymph
  • lymph enters vena cava in chest and bypass liver
• accessory glands - digestion

  • salivary glands
  • mucus
  • amylase
  • mostly for lubricant
  • pancreas
  • endocrine: glucagon and insulin
  • exocrine: enzymes --> duodenum (pancreatic duct)
  • liver
  • bile (gallbladder)
  • nutrients
  • duodenum (bile duct)
• digestion and absorption - carbs

  • poly --> di
  • enzyme: amylase
  • mouth - salivatory glands
  • pancreas
  • di --> mono
  • enzyme: on the border
  • monos: fructose, glucose, and galactose
  • absorption:
  • glucose and galactose
  • apical membrane: cotransport with na
  • raises cell concentration
  • basolateral membrane: facilitated diffusion
  • fructose: facilitated diffusion for both membranes
• digestion - protein

  • proteins --> peptide fragment
  • stomach: not much digestion
  • pepsin: chief cells
  • pepsinogen: inactive form
  • zymogen: inactive form of enzyme
  • cleaved to active pepsin by
  • hcl and pepsin
• digestion - small intestine

  • trypsin and chymotrypsin
  • secreted as zymogens
  • from pancreas
  • converted to active by
  • trypsin activating more zymogens
  • enzyme brush border
  • peptide --> amino acid
  • enzyme brush border
• absorption - amino acids

  • apical membrane: cotransport with na
  • basolateral membrane: facilitated diffusion
  • dipeptides and tripeptides
  • endocytosis
  • most are hydrolyzed to amino acids in epithelial cell

  overview: cap --> portal vein --> liver
• digestion - lipids

  • not water soluble - clumps
  • emulsion
  • bile salt
  • enzyme: lipase - from pancreas
  • fats = monoglyceride + 2 fatty acids
  • micelle = monoglyceride + fatty acid + bile salt
• absorption - lipids

  • apical membrane: simple diffusion
  • recombined into chylomicron
  • triglyceride and protein
  • basolateral membrane: exocytosis
  • enters lymph
  • bypass liver and blood
  • normal circulation
  • veins in thorax
• hdl and ldl - lipids

  • low density lipoprotein (LDL)
  • associated with atherosclerosis and heart disease
  • high density lipoprotein (HDL)
  • less risk for cardiovascular disease
• vitamins

  • fat soluble: a, d, e, k
  • fat pathway
  • water soluble: diffusion or mediated transport
  • vitamin b 12
  • needed for rbc production
  • intrinsic factors (stomach)
  • endocytosis
  • vitamin b 12 --> intrinsic factors --> receptors in illeum
• ions and minerals

  • na: countertransport or cotransport with other substances
  • k
  • absorbed in small intestine
  • absorbed/secreted in colon - concentration depends
  • diarrhea: loss of k
  • hco3
  • secreted into ileum and colon
  • diarrhea: loss of hco3
  • ca absorbed stimulates vitamin d
  • fe absorbed into blood - by need
• water absorption

  • 95% absorbed
  • solute transport creates a concentration gradient for osmosis
• food intake

  • suppress hunger
  • gi hormones
  • insulin
  • food in lumen of stomach/intestine
  • leptin (fat cells)
• gastrointestinal secretion

  • general control
  • presence of food
  • hormonal control
• stomach acid

  • eating = increase parasympathetic = increase acid (feed forward)
  • stretch of stomach
  • increase gastrin and histamine = increase acid
  • h2 antagonist reduces acid, increase gastrin and histamine
  • negative feedback
  • increase acid = increase secretin (decrease acid = increase hco3 in pancreas)
  • decrease acid when food leaves stomach
• intestinal hormones stimulate pancreatic secretions

  • secretin: increase hco3 in the pancreas to neutralize acid
  • cck: increase pancreatic enzymes
• gastrointestinal motility

  • pacemaker cells: sympathetic and parasympathetic
  • types: segmental, peristalsis, migration of motility (cleans digestive tract)
  • gastric motility
  • solid: up to 9 hours
  • liquid: exit within 3 mins
  • most motility: mix
  • regulation
  • feed forward
  • food in the stomach stimulates intestines
  • negative feedback
  • food/acid in the intestines slow stomach
• reproduction

  • cell types
  • 1/2 number of chromosomes = haploid
  • male: spermatozoa
  • female: ova
  • diploid: normal cells
  • 2 pairs of 23, mom and dad
  • chromosomes
  • female: xx
  • male: xy
  • gametogenesis: production of gametes
  • germ cells
  • divided by mitosis to make more
  • duplicates split: identical diploid germ cells
• meosis: chromosomes duplicate

  • duplicates stick together
  • cross over: exchange between maternal and paternal chromosomes
  • line up randomly
• meiosis 1

  • cell splits
  • duplicates stick together
  • 46 total
  • results are random

  meiosis 2

  • duplicates split
  • 23 total
  • identical cells except for cross overed onces