Human anatomy exam

Sensory Receptors

are sensitive to environmental changes and initiate impulses to the brain and spinal cord

Senses are divided into two general senses

General (somatic) senses and Special sennses

Receptors associated with skin, muscles, joints, and viscera provide

general (somatic) senses

Special senses

are senses whose sensory receptors are located in large complex organs in the head

The five special senses are

vision, hearing, equilibrium, taste, and smell

Olfactory receptors

chemicals must be dissolved in solution to be detected

Olfactory organ

olfactory epithelium in upper nasal cavity of nose (on the superior nasal concha)

Taste Receptors

chemoreceptors that are located in taste bud

Chemicals must be dissolved in saliva to be detected

Taste sensations

the rest of the taste buds of the five primary tastes provides sensations

(sweet, sour, bitter, umami)

Taste nerve pathways

gustatory cortex within parietal love

Sense of hearing

the organ of hearing is the spiral organ

(spiral organs are mechanreceptors)

Auditory (eustachian) tube

passageway which connects middle ear to nasopharynx (throat)

Cochlea

snail shaped portion

Vestibule

are between cochlea and semi-circular canals

function: static equilibrium

the mechanoreceptors

responsible for the sense of hearing are contained in the spiral organ (organ of corti) receptor cells located on the basilar membrane

primary auditory cortex

temporal lobes of cerebrum for interpretation

vestibulocochlear nerve

CN VIII

vestibular and cochlear

branch/nerve

static equilibrium

functions to sense the position of the head and help us maintain posture while motionless

The vestibule

the inner ear contains the two membranous chamber responsible for static equilibrium

final destination

triggers a sensory impulse which travels on the vestibular branch of the VC nerve to the pons which directs impulse to the cerebellum for interpretation

Dynamic Equilibrium

functions to prevent loss of balance during rapid head or body movement

The three semi circular canals

contains the organ responsible for dynamic equilibrium

each ampulla houses a secondary organ for dynamic equilibrium called the

crista ampullaris which contains a patch of “hair cells” in a mass of gelatin

vestibular branch of VC nerve cerebellum

hair cells to bed

Sensory receptors are called

photoreceptors

the organ of vision is the

retina of the eye

when photoreceptors are stimulated to threshold impulses travel within the

optic nerve

outer tunic (fibrous)

protection

cornea

transparent anterior potation

sclera

white posterior portion which is continuous with eyeball except where the optic nerve and blood vessels pierce through it in the back of the eye

Three distinct layers

the outer tunic (fibrous),Cornea, sclera,

Accommodation

the process by which the lens changes shape to focus on close objects

Pathway of light through eye

cornea

aqueous humor

lens

vitreous humor

photoreceptors in retina

\

Cones

photoreceptors for color vision produced sharp images

Rods

photoreceptors for night vision produce silhouettes of images

Visual Nerve pathway

optic nerve

thalamus

primary visual cortex

digestion

break down into small pieces

ingestion

taking food into the mouth

absorption

the passage of digested food from GI tract into blood stream for distribution to cells

Defecation

the elimination of undigested material from GI tract

Digestive process

ingestion

movement of food

digestion

absorption

Defecation

Alimentary canal

extends from mouth to anus

Digestive Organ

Mouth

pharnyx

esophagus

stomach

small intestine

large intestine

Accessory Organ

alimentary canal that help digest food

Accessory organs include

salivary glands

liver

gallbladder

pancreas

Mucosa

innermost (surrounds lumen)

composed of epithelium + CT (areolar) and small amounts of smooth muscle

epithelium extends into lumen=vili (increases surface area)

contains many glands that secrete mucus

Submucosa

beneath mucosa

composed of areolar CT, blood vessels, lymph vessels, and nerves

functions: nourishment of mucosa

carrying absorbed nutrients away

Muscularis

two layers of the muscle

a. circular muscle layer around submucosa

b. longitudinal layer around circular layer

c. function: movement of food through canal

Serosa

outermost layer

a. visceral peritoneum

b. function:

free movement of canal in abdominal cavity

lubrication

Intestinal peritoneal extension

mesentery

suspend the length of the intestine within abdominal cavity

mixing

mechanical digestion

* food+digestive+mucus
* circular muscle layer

Peristalsis

accomplished by movement of longitudinal muscle

propelling action

sphincter muscles play an important role in movements throughout the GI tract also

Sphincter

a strong circular muscle which prevents regurgitation of food

esophagus and stomach

gastroesophageal sphincter

stomach and small intestine

pyloric sphincter

small and large intestine

ileocecal valve

large intestine to outside

internal and sphincter

external and sphincter

innervation of the tube

resting &digesting

autonomic nervous system

parasympathetic- activates digestion

sympathetic- slows digestion

Post-ganglionic networks

submucosal plexus

myenteric plexus

submucosal plexus

controls secretions

myenteric plexus

controls peristalsis

Mouth

terms oral cavity and buccal cavity refers to the mouth

mouth is adapted to receives food and start mechanical and chemical digestion by chewing and mixing food with saliva

Salivary glands

salivary glands secrete saliva

saliva binds food together and begins chemical digestion of polysaccharides by the enzyme salivary amylase

Major salivary glands

parotid

submandibular

sublingual

parotid

largest lies over masseter mostly serous cells

Submandibular

floor of mouth lateral mix of serous and mucous cell

Sublingual

floor of mouth, medial, mostly mucous cells

Salivary secretion composition

each salivary gland is composed of 2 cells

mucous cells and serous cells

mucous cells

secrete mucus

serous cell

secrete watery substances containing the enzyme salivary amylase

Salivary secretion function

provide lubrication

bind food together

begin chemical digestion of carbohydrates

Enzymes

salivary amylase breaks polysaccharides into disaccharides

starch and glycogen

disaccharides

Pharynx

throat

passageway of food into esophagus (and air into larynx/tranchea)

Esophagus

passageway for food pharynx to stomach

location: mediastinum behind trachea goes through diagram at esophageal hiatus

many mucous glands

movement of food

gravity

peristaltic waves push what you swallow to gastroesophageal

gastro esophageal sphincter muscle relaxes

food moves into stomach all at once

hiatus hernia-herniationi of the cardiac region of the stomach through a weakened esophageal hiatus

resulting in esophageal tissue being exposed to gastric juice

stomach

term gastric refers to stomach

the stomach function to mix bolus into chyme and begin the chemical breakdown of protein

structure of the stomach

contains extra oblique layer in muscularis

Part of the stomach

cardiac region- around esophagus

pyloric region- near duodenum

macroscopic rugae

mucosal folds in

Micoscopically these rugar are formed by

gastric villi that project into lumen which result in the formation of …

Gastric pits- that are located between the gastric villi

gastic glands- are located along these gastric pits

Gastric juice-is secreted by these gastric glands

function of the stomach

mechanical digestion- churning

chemical digestion of protein-gastric juice

Gastric secretion (juice)

composed of mucus

digestive enzyme pepsin

hydrochloric acid

intrinsic factor

gastrin

digestive enzyme pepsin

function:protein digestion (into peptides)

hydrochloric acid

function:

denatures proteins

kills microbes in food

intrinsic factor

function: enables us to absorb B12

gastrin (hormone)

regulates other things

Types of gastric cells

mucous- secretes mucus

cheif cells- secrete pepsin

partietal cells-secrete HCL and intrinsic factor

G-cell- secrete gastrin

Regulation of gastric secretion

Neutral

parasympathetic- increases gastric secretion

sympathetic- decrease gastric secretion

Hormonal

gastrin-increases gastric secretion

cholecystokinin- decreases gastric motility

Three phases of gastric secretion

Cephalic phase

Gatric phase

intestinal phase

Cephalic phases

(30-50% of control)

increases parasympathetic due to sight, taste, smell, and thought food

Gastric phase

(40-50% of control)

stretch of stomach wall increases gastrin secretion which increases gastric secretion

ph changes after gastric release

Intestinal phase

5% decrease stomach activity

gastric absorption

includes some salts, water, lipid soluble , drugs and alcohol

mixing and emptying action

mixing of bolus of food+gastric juice=chyme

peristaltic waves of stomach puch chyme toward pyloric sphincter it relaxes and food moves into duodenum a little at a time

enterogastric reflex

ensures stomach slows down as duodenum fills

pancreas

location: inferior to stomach; retroperitoneal

structure of pancrease

endocrine cell produce hormones glucagon and insulin

most cells make up pancreatic acini which produces pancreatic juice