Week 4 Flashcards
(32 cards)
What are the basic features of the small intestine?
- 21-25 ft long
- Three regions: duodenum, jejunum, ileum
- Main site of digestion and absorption of food
What are the features of the mucosal layer of the small intestine?
- Total SA is 400-600x normal
- Plicae Circulares
- Permanent spiral folds of mucosa and submucosa in distal duodenum, jejunum and proximal ileum
- Intestinal villi/mucosal folds of simple columnar cells with microvilli
- Microvilli of columnar cells
- increase SA the most
What are the cells of the epithelium of the small intestine?
- simple columnar epithelium
- Surface absorptive cells (enterocytes)
- Goblet cells
- Microfold (M) Cells
- EC cells
- Paneth Cells
- Stem cells
Function of enterocytes?
- Specilized transport of substances from lumen to blood
- microvilliea increase SA
- intercellular junctions create a barrier between intercellular space and intestinal lumen
Function of goblet cells in small intestine?
- Secretes mucinogen that is converted into mucous to protect the epithelium
What is the function of Microfold (M) cells?
- Antigen presenting cell
- modified enterocyte
- Cover lympathic cells in lamina propria
Function of Enteroendocrine (EC) cells in small intestine mucosa?
- Make the same peptides hormones as they do in stomach (doesnt same which ones in either lecture)
What do Paneth cells do in the small intestine mucosa?
- Located primarily in distal ileum
- secrete lysozyme (antibacterial)
- regulate normal intestinal flora
How often do stem cells replace mucosa cells of intestine?
- restore epthelial cells every 5-6 weeks
- Paneth cells every 4 weeks
What is contained within the Lamina Propria in the small intestine?
- Occupies the space instead villi and in between intestinal glands (Crypts of Lieberkuhn)
- Has CT, lymphoid tissue, villus lacteals
- Lympoid nodules are known as Peyers Patches in ileum
- Intestinal glands (crypts of lieberkuhn)
What type of muscle is contained in the muscularis mucosae/externa in the small intestine?
- ICOL
Features of the submucosa in small intestine
- Submucosal glands only in duodenum
- Brunners glands
- Unique to duodenum
- Produce alkaline mucin to neautralize HCl
- Makes urogastrone to inhibit gastric HCl production
What structures are included in the large intestine?
- cecum iwht appendix
- colon
- rectum
- anal canal
What are the strucutral features of the large intestine?
- No special mucosal folds
- Lacks villi
- Main place of bacteria to produce
- Vit B12 (hematopoiesis)
- Vit K (coagulation)
- Contribute to feces
- Lots of mucus
What cells are contained in the mucosa of large intestine?
- Surface: simple columnar absorptive cells
- Crypts of Lieberkuhn (intestinal Gland)
- Numerous goblet cells
- Stem cells
- EC cells
What are the layers of the large intestine? Note anything different about them when compared to other GI layers.
- Musoca
- epithelium
- Lamina propria
- well developed GALT
- No lacteals
- Muscularis mucosae - ICOL
- Submucosa
- Muscularis Extera
- ICOL
- tenaie coli/haustra
- Serosa adventitia
- appendices epiploicae
What is an appendix epiploica? Where is it located?
- an aggregate of adipocytes surrounded by serosa
- located in the serosa in the large intestine
What make up taeniae coli?
- fascicles of outer longitudinal layer aggregate into three space bands in muscularis externa layer in large intestine
Layers of the appendix
- Same layers as large intestine
- Mucosa
- Submucosa
- Lymphatic nodules (germinal centers)
- Muscularis externa
- Very thick inner circular layer
- Much thinner outer longitudinal layer
Describe the epithelial layer of the rectum and anal canal
- simple columnar epithelium to anal valves (pectinate Line)
- colorectal zone
- variety of stratified epithelia distal of anal valves
- transitional zone
- changes to stratified squamous keratinized at anus
- squamous zone
What is contained in the lamina propria of the anal canal?
- sebaceous glands
- LAG
- hair follicles
- large veins
Layers of Anal Canal
- mucosa
- lamina propria
- muscularis mucosa
- ICOL, terminate at anal valves
- Submucosa
- fibroelastic tissue
- Musuclaris externa
- ICOL
- IC forms internal sphincter (SM)
- Adventitia
- External Anal sphincter
- skeletal muscle of pelvic floor
What contributes to cardiovascular disease?
- hypertension
- smoking
- high cholesterol
- atherosclerosis
- overweight
- can cause insulin resistance
What are the lab values for someone to be considered pre-diabetes or diabetes for the following tests
- Random plasma glucose
- Fasting plasma glucose
- 2-hr glucose during OGTT
- Hemoglobin AIC
