Bio 163 exam 4
how many layers are in the mucosa membrane and what are they?
3; epithelium, lamina propria, and muscularis mucosae
How many layers are in the GI tract?
4 layers
digestion
Breaking down food
What are memory cells?
Cells that remember a specific antigen so that if it returns, the body can quickly respond and are stored in the lymph nodes
what happens when the lower esophageal sphincters doesn't close or delays to close?
GERD; stomach acid enters esophagus causing a burning pain known as heart burn
Ingestion
Intake of food
what is the difference between specific and non-specific defenses?
Nonspecific defenses attack any pathogen that are external barrier, phagocytic cells, natural killer cells, fever, and inflammation. Specific defenses attack a specific identified pathogen which are cell-mediated resistance and antibody-mediated resistance.
What does immunity mean?
Resistance to disease
What are antibodies?
Substances created in the body to attack specific foreign antigens
describe the muscles of the esophagus
The upper third of the esophagus is skeletal muscle, the middle third has both skeletal and smooth muscle, and the lower third is smooth muscle.
what is the function of peristalsis?
To push substances through tubes in the body
what is the muscularis mucosae?
VERY thin layer of smooth muscle; helps with transport
Does the submucosal layer have blood vessels, glands, and lymphatic tissue?
Yes
What is the ileocecal valve?
a sphincter that controls the flow of material from the ileum into the cecum
what are class I cells?
all other nucleated cells, present antigens when they have become infected -only recognized by cytotoxic T cells that are then activated to kill any cells showing a specific antigen
what are the 4 regions of the large intestine?
ascending, transverse, descending, sigmoid
what is the right colic flexure?
bend between ascending and transverse colon
What is the left colic flexure?
bend between transverse and descending colon
what happens when the lower esophageal sphincter doesn't open?
causes burn and stretches out
what are the 2 regions of the muscularis called? What type of muscle?
circular layer and longitudinal layer smooth muscle
What are natural killer cells?
circulating blood cells with cytotoxic granules that destroy viruses and infected cells. they are the first line of defense and are non-specific
what is the function of the meissner's plexus?
control secretion and contraction
what is the function of sphincters?
control the passage of food or chyme through GI tract
what type of tissue is found in the submuscosa?
dense irregular/ connective tissue
what is the function of the stomach?
digestion and storage
What are pathogens?
disease/ infection causing organisms that lead to an immune response
Egestion
elimination of undigested food
What are B cells responsible for?
engulfs pathogens, displays antigens, antibody producers, produce memory B cells
what is chemical digestion?
enzymatic breakdown of food; primarily proteins
What is the duodenum?
first part of the small intestine, functions in digestion
What is the plicae circulares?
first set of folds in the small intestine
What is rugae?
folds in the stomach that allows it to expand
motility
food getting to where it needs to be
what are the functions of the mouth?
food intake, mechanical digestion, chemical digestion, taste
Why is there stratified squamous epithelium in the mouth, esophagus, and anus?
for protection, to prevent aberration
what are the 2 sphincters of the anal canal?
internal anal sphincter and external anal sphincter
Is the internal anal sphincter voluntary or involuntary?
involuntary
Muscularis of the mouth, pharynx, upper esophagus, and anus is...
involuntary skeletal muscle
95% of the muscularis is involuntary or voluntary? Is it smooth or skeletal?
involuntary; smooth
Describe the pancreas
it has both exocrine and endocrine functions in the digestive system
what are mature cytotoxic cells?
kills other cells that are infected in the cell body, DESTROYERS
What is the rectum?
last section of the large intestine that stores feces
What is the ileum?
located in the small intestine, high surface area for absorption of nutrients
what are the functions of saliva?
lubrication, chemical digestion
what are class II cells?
macrophages or B cells that engulf pathogens and present antigens. they are not infected and can only be recognized by Helper- T cells
what is another name for mechanical digestion?
mastication
What is the jejunum?
middle section of the small intestine, high surface area for absorption of nutrients
What are antigens?
molecules that have the potential to generate antibodies
what is the function of the muscularis?
motility/plexus
where do you see stratified squamous epithelium?
mouth, esophagus, and anus
what is the innermost layer of the GI tract?
mucosa
which layer comes in direct contact with food?
mucosa
what are the four layers of the GI tract?
mucosa, submucosa, muscularis, serosa
soft palate
muscles covered by stratified epithelium and the mucous membrane
what is the plexus of the muscularis called?
mycentric plexus
What is a plexus?
network of nerves/ nervous tissue
What is the endocrine function of the pancreas?
pancreatic islets of langerhans secrete insulin and glucagon INTO THE CAPILLARIES
What is mechanical digestion?
physical breakdown of food
What is haustra?
pouches in the large intestine
What is phagocytosis?
process by which a cell ingests and disposes of foreign material
What is the exocrine function of the pancreas?
produce pancreatic juice aka acinar cells
What is the lower esophageal sphincter?
regulates movement of food from esophagus to stomach, and prevents regurgitation of acidic stomach contents
What are helper T cells?
release cytotoxic, activates B cells,, activates T cells ,COMMUNICATORS
hard palate
roof of mouth, palatine bone, maxilla
what does mucosa form?
rugae
what are the villi in the small intestine?
second layer of folds
what is the function of the mucosa layer?
secretion and absorption
what is the function of the submucosa?
secretion and contains plexus
what is the outermost layer of the GI tract?
serosa
what type of epithelium are in the other GI organs?
simple columnar
What are cytokines?
small proteins that cause changes in many cells types secreted by activated Th cells
what type of muscle are the sphincters?
smooth muscle
what gland secretes the most saliva?
submandibular gland
what glands secrete digestive juices into the lumen? Where is it found?
submucosal gland; submucosa
Where is Meissner's plexus located?
submucosal layer
secretion
substance are released
What is deglutition?
swallowing
where does the pancreatic juices/bile enter
the duodenum
What is the anal canal?
the last segment of the large intestine, feces are passed through here
What is the pyloric sphincter?
the opening through which chyme leaves the stomach and enters the small intestine
What is the serosa layer the same as?
the peritoneum
What are macrophages?
they activate helper T-cells, engulf and display entigens
What are lymph nodes?
they house white blood cells, where specific immune responses occur, and they get swollen when sick
What is the lamina propria?
thin layer of loose connective tissue, contains capillaries
What is the microvilli of the small intestine?
third layer that looks like brushes
What is the teniae coli of the large intestine?
three bands of longitudinal smooth muscle in muscularis
Why do the other GI organs have simple columnar epithelium?
to aid in secretion and absorption
True/ False: The mucosa layer is stratified and produces extra mucous during defecation
true
GI tract
tube from mouth to anus
Absorption
uptake of nutrients into bloodstream
Is the external anal sphincter voluntary or involuntary?
voluntary
what is salivas made of?
water, mucus, and enzymes