BI210: FINAL

system of glands that secretes hormones that control many bodily activities

endocrine system

secreted signaling molecule that travels in the bloodstream

only cells with the proper receptor can respond to the hormone

hormone

long distance communication

similar to the nervous system, the endocrine system is a system of _____________________.

gland that secretes its hormones directly into the bloodstream

endocrine glands made of endocrine cells

endocrine gland

cells that express receptors for the hormone and respond to the hormone

target cells

things pulled from blood/interstitial fluid and are secreted to surfaces of the body

linked to epithelial surfaces

(sweat, mucus, tears)

exocrine secretions

NS innervates individual targets at the cellular level

endocrine system communicates with every cell that has a receptor for its hormone at the same time

hormones can stay intact in the bloodstream for hours to days at a time

compare and contrast the nervous and endocrine systems

hypothalamus

homeostasis center of the brain

extension of the hypothalamus

secretes hypothalamic hormones

posterior pituitary gland

separate gland from the hypothalamus and posterior pituitary gland

connected to the hypothalamus through a portal system

hypothalamus makes hormones and shuttles them to the anterior pituitary who will add its own hormones and then bring everything to the heart

anterior pituitary gland

the release of tropic hormones from the hypothalamus triggers/controls the release of hormones from the anterior pituitary

tropic control

GH

TSH

ACTH

LH

FSH

Prolactin

6 hormones of anterior pituitary

growth hormone -- stimulates muscles and skeleton to get bigger

GH

thyroid stimulating hormone

TSH

adrenocorticotropic hormone

ACTH

controls production of egg and sperm in testes and ovaries

function of FSH and LH

controls lactation

function of prolactin

oxytocin

ADH

hormones of posterior pituitary

controls urine production

function of ADH

controls contractions of uterus

manipulates ability to bond with other humans

oxytocin

anterior to trachea

where is the thyroid gland found?

follicular cells

parafollicular cells

2 cells making up thyroid gland

secretes thyroid hormone

thyroid hormone regulates metabolism (ATP) and increases rate of sodium potassium pump

function of follicular cells in thyroid gland

secretes calcitonin

calcitonin encourages deposition of calcium into bones (decreases blood calcium levels)

function of parathyroid cells

thyroid follicle

follicular cell

parafollicular cell

behind the thyroid gland

where is the parathyroid gland located?

secretes parathyroid hormone

PTH activates osteoclasts to leach calcium from bones and add it to blood

function of parathyroid gland

sits on top of kidneys

made of adrenal cortex and adrenal medulla

adrenal gland

secretes corticoids (hormones derived from cholesterol)

- glucocorticoids

- mineralocorticoids

- androgens

hormones of adrenal cortex

ACTH hormone

what controls the adrenal cortex?

sympathetic nervous system so that the body can automatically respond to danger/fear

fight or flight

what mechanism does the adrenal medulla use?

epinephrine

increases blood flow, sweat, pupil size, etc...

hormone of adrenal medulla

insulin

glucagon

hormones of pancreas

glucose storage

cells take up glucose from blood and store in muscles or liver as glycogen

function of insulin

releases and breaks down glycogen to release glucose to blood

function of glucagon

hollow, connected set of structures that food passes through

is continuous with the outside world

tract

solid organs that make digestive secretions

contributes to digestive system but food does not pass through them and organ is not hollow

accessory organs

break larger molecules into smaller molecules

function of digestive system

using enzymes and acids to break up food molecules

chemical digestion

physically breaking up food molecules

chewing, peristalsis, segmentation

mechanical digestion

rhythmic smooth muscle contractions that push food down the digestive tract

peristalsis

1) mouth chews food

2) food is swallowed -- goes to oropharynx and laryngopharynx

3) food goes through esophagus and then to stomach

4) duodenum receives food from stomach, then to jejunum and ileum

5) large intestine

6) rectum holds feces

7) anus excretes feces

process of food through the GI tract

1) mucosa -- epithelial and connective tissue

2) submucosa -- connective tissue/blood vessels

3) muscularis externa

-- divided into circular and longitudinal muscle

4) serosa -- outer layer of connective tissue

the 3 GI tract tunics

muscle fibers go in a circle

narrows the GI tube when it contracts

role of circularis muscle of muscularis externa

pushes food forward when muscles contract

role of longitudinal muscle of muscularis externa

parietal layer covers wall of abdominal cavity

visceral layer covers surface of abdominal organs

describe the serous membrane of the GI organs

double layer of peritoneum anchoring the small intestine to the abdominal wall

mesentery

fold of free floating, visceral peritoneum hanging off of greater curvature of stomach that drapes over large and small intestine for cushioning and protection

greater omentum

contains immune cells

if inflammation in abdomen, omentum will move over site of inflammation to help it heal

immune function of the greater omentum

fold of peritoneum anchoring colon to posterior abdominal wall

mesocolon

double layer of peritoneum hanging from lesser curvature of stomach

connects stomach and duodenum to liver

lesser omentum

greater omentum

lesser omentum

mesocolon

mesentery

organs completely surrounded by visceral peritoneum and is connected by a mesentery

stomach, liver, jejunum, ileum, transverse colon, sigmoid colon, spleen

intraperitoneal

organs located behind the peritoneum and not suspended by a mesentery

kidneys, adrenal glands, esophagus, duodenum, ascending/descending colon

retroperitoneal

saliva solubilizes taste molecules so the fit into taste

role of saliva

parotid, submandibular, and sublingual salivary glands

put together, they make the components of saliva

salivary glands

histatin -- would healing, catalyzes collagen

lysozyme -- bacteria fighting molecule, antibacterial agent

bicarbonate -- neutralizes acidic compounds

molecules in saliva and their role

chewed food that goes down the esophagus via peristalsis

bolus

mucosa, submucosa, muscularis, serosa

highly stretchy and folded to allow bolus to pass through

structure of esophagus

transport bolus from pharynx to stomach

function of esophagus

hole in the diaphragm that the esophagus passes through

esophageal hiatus

prevents stomach acid from entering esophagus

function of lower esophageal sphincter

ring of smooth or skeletal muscle that can close completely to create a doorway into another body space

sphincter

stratified squamous epithelium

(deals with friction from food)

epithelium of esophagus

mucosa, submucosa, muscularis externa, serosa

muscularis externa has 3 layers

(oblique, circular, longitudinal muscle)

layers of stomach

stomach partially digests proteins using HCl and pepsin

HCl -- denatures proteins

pepsin -- breaks peptide bonds -- cleaves proteins into smaller strips

explain chemical digestion in the stomach

produces bicarbonate mucus to protect its epithelium

how does the stomach protect its epithelium from its harsh environment

stores up to 1L of food so we can digest slowly while doing other things

how does the stomach act as a holding tank?

sphincter between stomach and duodenum

controls release of stomach content to duodenum since small intestine cannot digest food quickly and must do it in segments

pyloric sphincter

secretes acid (HCl)

function of parietal cells

secretes pepsinogen

pepsinogen activated by HCl into pepsin

pepsin breaks peptide bonds of proteins

function of chief cells

secretes digestive hormones

regulates digestion

enteroendocrine cells

simple columnar epithelium with a layer of mucus covering it

epithelium of stomach

helps stomach expand

purpose of rugae of stomach

where the products of HCl and pepsin are generated

purpose of gastric pits of stomach

1) mechanical digestion

2) chemical digestion

3) holding tank

4) protection

4 functions of the stomach

1) cardia region

2) fundus

3) body

4) antrum

5) pylorus

5 regions of the stomach

antrum

cardia

fundus

body

pylorus

8-10 inches

shortest segment

length of duodenum

receives stomach contents

receives digestive enzymes from liver and pancreas

role of duodenum

produces enzymatic secretions helping digest carbs, fats, proteins

role of pancreatic secretions in digestion

14 feet each

length of jejunum and ileum

1) digestion

2) absorption!

almost all nutrient absorption occurs in jejunum and ileum

general functions of small intestine

small intestine has circular folds

each circular fold has villi

each villi/simple columnar cell has microvilli

how does the small intestine increase surface area?

absorbs materials such as pepsin, amino acids, etc

role of capillaries in small intestine villi

duodenal glands are unique to the duodenum only

secretes an alkaline mucus to protect the duodenum from acidic chyme

role of duodenal glands

found throughout small intestine

secretes digestive hormones and antimicrobial compounds

role of intestinal glands

junction between small and large intestine

ileocecal junction

extract liquid from remaining material and hold it as feces in the rectum

some digestion -- large intestine is a gut microbiome that can break down some undigested components

function of large intestine

digested food from large intestine stored in rectum as feces and goes through anus

how does the body excrete food waste?

seed population for the entire gut microbiome

appendix