exam 2 Flashcards
Functions of digestive system
Take food in
Break down into nutrient molecules
Remove waste from the body
Processes definitons
- Ingestion: eating
- Propulsion
Moves food through GI tract (swallowing) (voluntary)
Peristalsis (involuntary) - Mechanical digestion
Chewing, churning, segmentation - Chemical digestion
steps in which enzymes secreted into lumen of GI tract break down complex food molecules to their mechanical building blocks
-Absorption
Passage of digested end products from lumen of GI tract through mucosal cells by active/passive transport into blood or lymph - Defecation
Eliminates indigestible substances from the body via anus in the form of feces
Segmentation:
mixes food w digestive juices and makes absorption more efficient by repeatedly moving different parts of food mass over intestinal walls
Which Papillae house the taste buds
Fungiform, Vallate, and Folliate
Two primary sections and fucntions
GI Tract (alimentary canal)
Digest foods, break it into smaller fragments, and absorb digested fragments.
Mouth, pharynx, esophagus, stomach, small intestine, large intestine
Accessory organs
Teeth, tongue, gallbladder, digestive glands, liver pancreas
Produces secretions that help break down foodstuff
Regulation of digestion
provocation: Mechanical and chemical stimulation
Effectors: smooth muscle and glands
Control: neurons and hormones
Prime mean for regulation is to control the luminal conditions
Splanchic circulation
the blood flow to the abdominal gastrointestinal organs including the stomach, liver, spleen, pancreas, small intestine, and large intestine
the hepatic portal circulation collects nutrient rich venous blood draining from digestive viscera & delivers to the liver
Histology of GI tract
- Mucosa- innermost layer
-simple columnar epithilum - Submucosa- Areolar CT
- Muscularis Externa
- Circular layer- (deep layer) smooth muscle & forms sphincter
- Longtitufianl layer- (superficial layer) smooth muscle
- Serosa or retroperioneal
- serosa: Areolar CT w/ mesothelium, simpel squamous epithil.
- Retroperitoneal has both adventitia & serosa
functions of 4 layers of GI Tract
mucosa,submucosa….
Mucosa-
secrete mucus digestive enzymes, & hormones
Absorbs end products of digestion into the blood
Protect against infections disease
Submucosa-
contains supply of blood & lymphatic vessels, lymphoid follicles, nerve fibers that supply surrounding tissues
Muscularis externa
Responsible for segmentation and peristalsis
Serosa
only present in abdominal cavity
Serosa replaced by adventitia
Retroperitoneal have both adventitia and serosa
Nerves
helps control activity of glands
Enteric (intrinsic vs. extrinsic
intrinsic
- short reflexes which respond to stimuli within GI tract
Extrinsic
- long reflexes allow extrinsic controls to influence digestive activity
-Connect GI tract to brain and spinal cord
Myentric
lies between circular and longitudinal muscle of muscularis externa
Mouth histology + lips n cheek histolgy & function
Mouth- stratified sqaumous epithilum
Lips & cheek
- helps keep food between teeth
- Skeltal muscle covered externally by skin
hard & soft palate
- Palate- forming of the roof of mouth
- Hard palate is anterior & underlain by palatine bones
- Soft palate is posterior & formed mostly of skeletal muscle that rises to close off nasopharynx when swallowing
Tongue muscles (intrinsic & extrinsinc)
Intrinsic skeletal muscle: not attached to bone, allow tongue to change shape but not position
Extrinsic skeletal muscles: alter tongues position, allow to move side to side, retract it, and protrude it & extend to tongue from points of origin on bones of skull or soft palate
Papillae
Filiform papillae - most anterior,smallest and most numerous, contains keratin, rough surface helps for licking and manipulating foods
Fungiform papillae- scattered widely, each have vascular core give reddish hue
Vallate papillae- V-shaped row @ back of the tongue
Foliate papillae- located lateral aspect of posterior tongue
Salivary glands (intrinsic & extrinsic)
Intrinsic- Scattered through oral cavity mucosa augment the output slightly
Extrinsic-Lie outside the oral cavity and empty secretions into it
Salivary glands
-Parotid
- submandibular
- Sublingual
locations & functions
- Parotid
- anterior to ear
- Help w/ chewing, digestion, and keeping the mouth lubricated
- Submandibular
- helps w/ digestion, cleaning, swallowing, & taste
- medial aspect of the body of the mandibular body
- Sublingual
- helps w/ dental hygiene and lubricates mouth
-Lies anterior to the submandibular gland under the tongue
Salivary gland cells
- Serous
produce watery secretion containing enzymes, ions, and tiny bit of mucin - Mucous
Produce mucus
Saliva composition
97-99.5% of water
The rest is composed of
Electrolytes
digestive
Enzymes
Protein mucin, lysozyme and IgA
Metabolic waste
Saliva control & amount
- Control
Controlled by parasympathetic division of autonomic NS - Amount
Average output of saliva is about 1500 mL/day
What are two sets of teeth
Primary and permanent dentitions
Primary: consists of deciduous teeth or baby teeth
permanent teeth are js permanent
Teeth names & function
Incisors (central & lateral) - cutting/nipping food off pieces of food
Canine- tear and pierce
Premolars- grinding and crushing
Molars- grinding and crushing
Third molars (wisdom)
Teeth #s
primary & permanent
Primary has 20 teeth
Permanent has 32 teeth
Teeth structure
Two major regions: crown and root
Root: portion of tooth embedded in the jaw bone
Teeth
Crown, Neck,Cavity,Gingiva,Cells
- Crown
Is exposed part of the tooth above gingiva or gum - Neck
Connects the crown and the root - Cavity
result from bacterial action that gradually demineralized enamel and underlying dentin - Gingiva
Surrounds tooth like a tight collar - Cells
Odontoblast: cell type that secretes and maintains the dentin