Digestive system
process food, extract nutrients and eliminates waste
“Disassembly line”
Ingestion
intake of food
digestion
breakdown of food
absorption
uptake of nutrients
egestion
elimination of undigested food
motility and secretion
digestive tube (4 layers)
mucosa- secretion
submucosa- secretion (nervous tissue)
muscularis-motility (nervous tissue)
serosa- outer connective covering
salivary glands
produce saliva that help with the process
salivary amylase
deglutition
swallowing (pharynx and esophagus)
peristalsis
muscle contractions
stomach
food storage- 4 liters of food
mechanical digestion- grinding and pulverizing action
initial chemical digestion-primarily proteins
rugae- mucosa
muscular- 3 layers of cells
gastric pits
split into 2 or 3 gastric glands
1. mucous red cells secrete mucous
2.chief cells secrete pepsinogen
3. parietal cells secrete Hydrochloric acid
4. Enteroendocrine secrete release hormones
decreases pH
gastrin-stimulates parietal cells to release HCL and chief cells to release pepsinogen
histamine- release of acid
5. Chyme enters small intestine
duodenum
pancreatic juices./bile enter here
Surface area
increase absorption of nutrients 1. circular ridges (folds of tissue) 2. Villi/villus 3. microvilli mucosa layer- crypts similar to pit
gastric inhibiting peptide
inhibit stomach function and promote insulin release
secretin
stimulate pancreas and liver, inhibit parietal cells
CCk
inhibits stomach, stimulate pancreas, liver and gallbladder
pancreas
release of juices- parasympathetic system and CCK and secretin
Liver/gallbladder
produces bile bile salts- digestion Fat emulsification globin= reusable protein heme= broken down into iron and bilirubin bilirubin- toxic
GNC
gastric neuronal circuits
reflexes that stay within the digestive system
Cephalic stage
cause sight smell and thought of food
response- increase secretion in stomach
increase muscle contractions
Gastric pahse
food enters stomach
Afferent: mechanoreceptors
efferent: target secretions+muscle
response: increase in secretions, muscle contraction
Intestinal phase
food entering into small intestine Afferent: mechanoreceptors sense stretch efferent: neurons that target secretion response:decrease in secretions increase in intestinal secretions muscle contraction in small intestine
Heptatic portal system
nutrients go to liver
portal system
2 capillary beds- villus and liver
Endocrine system
chemical messages
slower, indirect communication
nervous system
electrical and chemical signals
fast, direct communication
endocrine gland
secrete hormone into blood stream
exocrine
require a duct(tube) to transport secretions
hormones
steroid or protein
steriod
made from cholesterol
testosterone and estrogen
protein
polar and anionic
insulin and amino acids
Path of hormone
- hormone travels through blood stream
gland to tissue - tissue is determined by special receptors
plasma membrane (hydrophilic)
cytoplasm (hydrophobic)
3,4,5. receptors turn on/off gene expression
receptor complex must be deactivated when finished
NEGATIVE FEEDBACK
pancreas
both exocrine and endocrine
exocrine-pancreatic juices
endocrine- hormones
insulin
related when increased blood pressure
uptake glucose
glucagon
released when low blood glucose
stimulates release of stored glucose
type 1 diabetes
auto immune system
no insulin
type 2 diabetes
insulin insensitivity
large intestine
about 1.5 meters long
takes about 9L of water
pituitary gland
regulates endocrine organs
anterior- synthesis own hormones
regulated by hypothalamus
posterior- secretes horses from hypothalamus
hypothalamic neurons
produce hormones
RH to H1 to H2 which causes a change in target tissue
ovary
follicular cells, oocytes, blood vessels and tissue
ovulation
LH and must occur in uterine tube
corpus luteum
cells become yellow and cholesterol goes into progesterone
LH
Uterus
which muscular chamber
myometrium- smooth
endometrium- cell division and growth to prepare for pregnancy
menstruation
shed every month if not pregnant
birth control
low levels of estrogen and progesterone
prevents signals for egg to mature
cervix
entry point of uterus
mucous
thick before ovulation
prevent sperm from entering
thin after ovulation
host to HPV
Vagina
muscular canal
receive sperm and egg
vaginal rugae
stimulate the penis
Male repro
tubes-epididymis, vas deferens, urethra
glands- seminal vesicle and prostate
3 types of cells
interstitial- between the tubules
germ cells- divide and become sperm
sustentacular- protect the germ cell
spermatogenesis
- spermatogenic
- sustentacular cells surround developing sperm
- spermatogonium travels towards lumen
undergoes meiosis - mature sperm develops flagellum and loses its cytoplasm
FSH
stimulates sustentacular cells to secrete ABP
LH
stimulates interstitial cells to secrete testosterone
ABP
androgen binding peptide- transport testosterone
epididymis
sperm maturation and storage
vas deferens
tube that carries sperm to urethra
seminal vesicle
causes sperm to stick to walls of vagina
prostate gland
break down seminal vesicle fluid to sperm can swim
Bulhourethral gland
liquid to preejaculatory
penis
3 cylinders of erective tissue
smooth muscle, connective tissue, blood vessels