Histology - June 19 block 2 Flashcards
Where are satellite cells located?
Satellite cells, which are located just outside the sarcolemma underneath the muscle basement membrane, control the repair of skeletal muscle. They become activated by cues induced by muscle injury or disease.
How do muscles get blood?
Generally, an artery and at least one vein accompany each nerve that penetrates the epimysium of a skeletal muscle. Branches of the nerve and blood vessels follow the connective tissue components of the muscle of a nerve cell and with one or more minute blood vessels called capillaries.
2 arteries, one vein and nerve through CT, with capillary system piercing each endomysium.
what does syncytial mean?
A multinucleate cell which can result from multiple cell fusions of uninuclear cells (i.e., cells with a single nucleus), in contrast to a coenocyte, which can result from multiple nuclear …
What proteins does the Z line contain?
desmin and alpha-actinin.
What does alpha-actinin do in skeletal muscles?
anchors the barbed end of actin filaments to the Z disk
Does smooth muscle have sarcomeres?
No.
At the top of a T tubule, what can be bound?
sodium???
What is the purpose of laminin?
A protein that shares several properties with fibronectin. … In the extracellular matrix, laminin can bind other laminin molecules as well as other proteins like collagen, which helps to reinforce the extracellular matrix structure
Dystrophin is a protein found in muscle cells. It is one of a group of proteins that work together to strengthen muscle fibers and protect them from injury as muscles contract and relax. It links muscles to the cytoskeleton and ECM. it links to Laminan 2 and others].
How do muscarinic vs. Nicotinic receptors differ?
G proteins vs. ligand gated
Muscarinic acetylcholine receptors belong to a class of metabotropic receptors that use G proteins as their signaling mechanism. … By contrast, nicotinic receptors use a ligand-gated ion channel mechanism for signaling.
What are subneural clefts? and what is their arrangement?
ACh gated channels at top
Voltage gated Na+ channels in bottom half
What are dense bars in the presynaptic terminal bulb?
Ca2+ channels are localized around linear structures on the pre-synaptic membrane called dense bars
Vesicles fuse with the membrane in the region of the dense bars.
How does end plate potential work?
ACh released into the neuromuscular junction binds to, and opens, nicotinic ACh receptor channels on the muscle fiber membranes (Na+, K+, Ca2+).
Opening of nACh receptor channels produces an end plate potential, which will normally initiate an AP if the local spread of current is sufficient to open voltage sodium channels.
What terminates the process?
Acetylcholinesterase
At the T-tubule triad, what are the two proteins of import?
Dihydrophyridine (voltage sensor) plucks RYANODINE out of the cisternae of the sarcoplamic reticulum.
How does this pump work? Ca2+ ATPase -
It gets CA back in sarcomeres - but I don’t know how.
Nuclear chain vs bag fiber?
A nuclear chain fiber is a specialized sensory organ contained within a muscle. Nuclear chain fibers are intrafusal fibers that, along with nuclear bag fibers, make up the muscle spindle responsible for the detection of changes in muscle length. … They are static, whereas the nuclear bag fibers are dynamic in comparison
A nuclear bag fiber is a type of intrafusal muscle fiber that lies in the center of a muscle spindle. Each has many nuclei concentrated in bags and they cause excitation of both the primary and secondary nerve fibers. There are two kinds of bag fibers based upon contraction speed and motor innervation.
What are muscle spindles and Golgi tendon organs?
Unlike muscle spindles (located in parallel with muscle fibres), Golgi tendon organs are located in tendons near the myotendinous junction and are in series, that is, attached end to end, with extrafusal muscle fibers. Golgi tendon organs are activated when the tendon attached to an active muscle is stretched.
What is a gamma motor neuron?
involved in reflexes and involved in adjusting muscle tension in spindles
What are motor neurons?
a nerve cell forming part of a pathway along which impulses pass from the brain or spinal cord to a muscle or gland.
What are intercalated discs?
Intercalated discs are part of the sarcolemma and contain two structures important in cardiac muscle contraction: gap junctions and desmosomes. A gap junction forms channels between adjacent cardiac muscle fibers that allow the depolarizing current produced by cations to flow from one cardiac muscle cell to the next.
Desmosome, Fascia Adherens, and gap:
TRANSVERSE component (right angles)- desmosome and fascia LONGITUDINAL (parallel) - gap.
In cardiac cells, does calcium trigger contraction?
Differences between atria and ventricles
The myocardium found in the ventricles is thick to allow forceful contractions, while the myocardium in the atria is much thinner. The individual myocytes that make up the myocardium also differ between cardiac chambers.
When does the heart become an endocrine organ?
When is ANP secreted by heart - which becomes an endocrine organ?
secreted from both right and left atria ANP is secreted in response to increased blood flow OR increased venous pressure.
Right (and left) atrial heart difference?
Yes, fewer ttubes, smaller, and special granules which act on kidneys to cause sodium and water loss - these OPPOSE aldosterone and antidiuertic hormone - whose effects on kidneys result in sodium and water conservation.
Main function of ANP?
The main function of ANP is causing a reduction in expanded extracellular fluid (ECF) volume by increasing renal sodium excretion.
What do diueretics do to your heart?
Diuretics, better known as “water pills,” help the kidneys get rid of unneeded water and salt. This makes it easier for your heart to pump. These medicines may be used to treat high blood pressure and ease the swelling and water buildup caused by many medical problems, including heart failure
Smooth muscles - characterisitcs?
no ttubes, caveloae near surface, leaky calcium channels, myofilaments form crisscross network; thin filaments have actin and tropomyosin - smooth muscle proteins (caldesmona and calponin) No troponin
In smooth muscles - where we also see thick filaments of myosin arranged in side polar design (striated bipolar). Sliding is similar to skeletal.
Calponin and caldesmon, constituents of smooth-muscle thin filaments, are considered to be potential modulators of smooth-muscle contraction. Both of them interact with actin and inhibit ATPase activity of smooth- and skeletal-muscle actomyosin.
What does calmodulin complex do in smooth muscles?
Activates myosin light chain kinase - the enzyme responsible for phophrylation of myosin. ?
Sex Hormones via cAMP is an example of non-neural control:
Estrogens increase cAMP and promote phosphorylations of myosin and CONTRACT of muscle -
Progesterone has opposite effect - decreases CAMP, promoting dephosphorylation of myosin, RELA
What are key filaments in smooth muscle?
Desmin and Viminetin
Dense bodies in smooth muscle?
They contain alpha-actinin and desmin - similar to Z lines of striated . Both thin and intermediate insert into dense bodies that transmit contractile force to adjacent muscles and the surrounding network
Visceral smooth muscles?
Single-unit smooth muscle, or visceral smooth muscle is a type of smooth muscle found in the uterus, gastro-intestinal tract, and the bladder. In SUVSM, a single smooth muscle cell in a bundle is innervated by an autonomic nerve fiber.
UNITLATERAL vs. Multiunit
Many smooth muscles are like this - large sheets such as found in walls of hollow viscera - intestines, uterus - with a lot of gap junctions, poor nerve supply.
Function in syncytial fashion as a single unit. vs. smooth muscles in eye which is a multiunit - with rich innervation that can produce precise and graded contractions
What can single unit smooth muscles generate?
Slow waves -
- modulated by postganglionic Parasym neurons release ACH, which bind to muscainic or receptors.
- postganglionic sympathetic neurons that release NE - binding to a1 and b2 adrenergic receptors.
- hormones such as estrogen (CONTRACT), progesterone (RELAX) or Oxytocin generating IP3, IP3 opens gated ca2_ channels in cisternae
How does nerve supply to smooth muscle differ from skeletal?
organs with smooth muscles generally have spontaneous activity - not looking for stimuli. The nerve supply modifies activity rather than initiating.
What stimulates the sympathetic nervous system?
Often called the emotional brain, the amygdala pings the hypothalamus in times of stress. The hypothalamus then relays the alert to the sympathetic nervous system and the signal continues on to the adrenal glands, which then produce epinephrine, and NE better known as adrenaline
In addition to contractile activity, what else can smooth muscles do?
Synthesize collagen, elastin and proteoglycans
What muscles do not have gap junctions?
Skeletal muscle cells lack gap junctions for the simple reason that they do not need them. Skeletal muscles are not single cells.
nor do multiunit smooth.
What are alpha 1 and alpha 2 receptors?
Alpha 1 receptors are the classic postsynaptic alpha receptors and are found on vascular smooth muscle. … Alpha 2 receptors are found both in the brain and in the periphery. In the brain stem, they modulate sympathetic outflow.
What receptor can only be excited?
Nicotinic receptors are all excitatory, but muscarinic receptors can be both excitatory and inhibitory depending on the subtype.
the parasympathetic effects (such as a slowed heart rate and increased activity of smooth muscle) produced by muscarine muscarinic receptors — compare nicotinic
Nicotinic receptors function within the central nervous system and at the neuromuscular junction. While muscarinic receptors function in both the peripheral and central nervous system, mediating innervation to visceral organs.
Where are nicotinic and muscarinic receptors located?
Muscarinic receptors predominate at higher levels of the central nervous system, while nicotinic receptors, which are much faster acting, are more prevalent at neurons of the spinal cord and at neuromuscular junctions in skeletal muscle.
Does skeletal muscle have muscarinic receptors?
Muscarinic receptors respond more slowly than nicotinic receptors. … Muscarinic receptors do not affect skeletal muscles, but do influence the exocrine glands as well as the inherent activity of smooth muscles and the cardiac conduction system.
Syncitia?
multinucleated cell that can not mitose
anisotropic vs isotropic?
diffusion varies vs is same -
When the properties of a material vary with different crystallographic orientations, the material is said to be anisotropic. Alternately, when the properties of a material are the same in all directions, the material is said to be isotropic.
What does high creatine kinase mean? (M Line)
CK stands for creatine kinase, an enzyme that leaks out of damaged muscle. When elevated CK levels are found in a blood sample, it usually means muscle is being destroyed by some abnormal process, such as a muscular dystrophy or inflammation.
Phospholamban?
is a 52-amino acid integral membrane protein that regulates the Calcium (Ca2+) pump in cardiac muscle cells.
Cardiac cells - run on fatty acids - where are they stored?
as triglicerides in lipid droplets seen in cardiac muscle cells. Glyogen also present for emergencies - stress
What acts against aldosterone and antidiuretic hormone (that in kidneys) conserves sodium and water?
ANP granules mostly in right atrium
LOWERS BLOOD PRESSURE
Secreted in response to increased venous pressure or increased blood volume
A LOT Of Dilute Urine. GETS RID of sodium….
and dilates blood vessels
reduce plasma volume by at least 3 mechanisms: increased renal excretion of salt and water, vasodilation, and increased vascular permeability. … Thus ANP-induced increases in endothelial permeability may be critical to the ability of ANP to lower arterial blood pressure.
Secreted in response to increased venous pressure or increased blood volume.
Getting sodium and water to LEAVE the body, thereby??? making the blood more fluid?
ANP functions include the following.
- ANP increases glomerular filtration pressure and glomerular filtration rate (via vasoconstriction of the efferent arteriole) and decreases Na+ resorption by the proximal convoluted tubule (PCT). These actions produce natriuresis (increased Na+ excretion) in a large volume of dilute urine.
- ANP inhibits secretion of antidiuretic hormone (ADH) from the neurohypophysis.
- ANP inhibits secretion of aldosterone from the adrenal cortex (zona glomerulosa).
- ANP inhibits secretion of renin from juxtaglomerular cells.
- ANP causes vasodilation of peripheral and renal blood vessels.
embryonic devel of skeletal vs cardiac?
splanchnic mesoderm
skeletal - fuse into syncytial cells -
Cardiac - align chainlike, and form complex junctions between their extended processes.
Spontaneous rhythmic contraction - initiitated by Purkinje fibers in nodes. run by symp and parasym nerve fibers
mechanics of contraction in skeletal vs cardiac muscles?
skeletal - voltage activated calcium release
T tube has voltage gated sensor to DHP receptor
Ryan releases CA, proportional to membrane voltage
Cardiac - calcium activates calcium release
t tube has CA channel to DHP receptor
Ryan releases CA proportional to CA entry.??
What muscles have no CELL _ CELL junctions?
skeletal - they don’t need them, they are long.
Smooth muscles, tightly packed, narrow part lies with adjacent broad
scalloped border when contract, like a corkscrew
at poles of nucleus are mitochondria, polyribosomes, cisternae of rer, glycogen granules, and golgi. Pinocyctotic vesicles caveolae are frequent
NO T tubes
smooth muscle proteins?
caldesmon and calponin. Myosin arranged in side polar - contract w/ actin and myosin sliding similar to striated
Smooth muscle concentration?
influx of CA, myosin interacts with actin only when light chain is phsophorylated using calmodulin.
MLCK - light chain kinase
CA + Calnodullin - > myosin kinase-> light chain -> mysoin ATPase -> head attached with actin - contraction by sliding
How do smooth muscles relax?
Nitrous Oxide
neural crest cells?
dorsal root ganglia, sympathetic chain ganglia, all post ganglionic sym and parasym ganglia, pia, arachnoid, schwann and satellite.
if you see GFAP?
astrocyte (NOT neural crest - don’t know why I thought it was).
Are ependymal cells joined together my tight junctions?
No - that’s how the CSF gets thru.
What can pass thru the BBB?
Water, gases, small lips - glucose and amino acids via carrier mediated transport
Dysphagia?
is the medical term for swallowing difficulties. Some people with dysphagia have problems swallowing
HCO3? Are surface mucous cells attached to one another?
Bicarbonate. yes, via juxtaluminal tight junctions. They secrete mucous and HCO3
What cells do gastric glands consist of?
Stem cells (migrate upward and downward - every 4 - 7 days replacing cells)
muscous producting Mucous neck (mucus)
Parietal (HCL, HCO3 into blood stream (alkaline tide), Intrinsic factor (need for B12 absorption)
Chief cells (pepsinogen and lipase)
Enteroendocrine
G Cells - (gastrin in response to meal) ANTRUM - stim: HCI in parietal, histamine release in enterochromaffinlike ECL, if ULCERS - can take out Antrum to cut down on HCl
ECL cells - secrete serotonin and histamine (stim HCl)
D cells - SOMATOSTATIN - inhibits G cells and ECL cells
Antrum?
Lots of G cells (which secrete Gastrin which promote HCL in parietal - so if ulcers, take out antrum.
Zollinger Ellison syndrome?
excess gastrin secretion due to malignant tumor - too much HCL produced. Peptic ulcer can be this problem.
If HCL production is low, what may happen?
Gastrin will fire - upping HCl.
a condition in which a gastrin-secreting tumor or hyperplasia of the islet cells in the pancreas causes overproduction of gastric acid, resulting in recurrent peptic ulcers.
Arrangement of gastric pits?
These glands are narrow tubules composed of three major cell types: zymogenic, parietal, and mucous neck cells. At the base of the gland are the zymogenic (chief) cells, which are thought to produce the enzymes pepsin and rennin.
What stimulates parietal cells to produce HCI?
Gastrin, Histamine,
Parietal cells secrete acid in response to three types of stimuli: Histamine, stimulates H2 histamine receptors (most significant contribution). Acetylcholine, from parasympathetic activity via the vagus nerve and enteric nervous system, stimulating M3 receptors.
Small intestine inner luminal surface? layers?
plicae circulares (valves of kerckring0 , villi, microvilli,
Cells covering villi?
absorptive - enterocytes - possess microvilli - coated in glucocalyx w/ lots of enzymes - sucrase, lactase, enterokinase (converts inactive to active pancreatic enzyme typsinogen).
What do enterocytes do?
absorb carbs, protein, lipids, vitamins, CA2, and FE2 (iron) from lumen and transport to blood or LYMPH
Enterocytes and everything but fat?
absorbs carbs, proteins, water soluable vitamins, CA2 and Fe2 - via various mechanisms. How they enter and exit to blood varies.
ie - carbs, glucose enters via NA+ dependent glucose transporter, but fructose via diffusion using GLUT5 trasnporter -
Proteins - broken into Amino acids - enter enterocytes via secondary active transport -
Vitamins thru diffusion, B12 absorbed in ILEUM, need intrinsic factor
CA2 - requires Vitamin D produced in Kidneys
FE
goblet cells in small intestine?
Lots - synthesize mucinogen which is stored as granules.
Fat cells and enterocytes ?
Long fatty chain - delivered to lacteals lymph
Short - to portal blood
Fat cells and enterocytes ?
Long fatty chain and fat soluble Vitamins - ADEK enter via micelle packaging w/ fatty acid-binding proteins - resynthesized into triglycerides?? eventually all
delivered to lymph via lacteals
Short - enter directly through diffusion, and exist same - to portal blood
How is fat broken down in GI system?
Bile salts.
Crypts of Lieberkuhn
stem cells - replacing enteroctyes every 3 - 6 days
Paneth Cells -BACTERIA fighters - base of intestinal glands, secrete Lysozyme, TNF, and DEFENSINS (increases membrane permeability of bacteria by forming ion channles)
Enteroendocrine cells
I cells - CCK
S cells Secretin (fireman)
K cells - GIP
L cells GLP
Mo cells - motilin
CCK?
stimulates PANCREAS (acinar cells)
BILE release (contraction) and oddi relax
decrease HCl secretion and gastric emptying,
increases pepsingogen secretion
secretin?
nature’s antacid - response to H+ (protons) and fatty acids in gut.
Stim release of Bicarb (HCO3 from Pancreas and Liver biliary tract
K cells - GIP?
stim insulin from islets - in response to oral admin glucose
L cells? GLP-1?
stim insulin when hyperglycemia, inhibits postprandial glucagon form islets
GALT (gut associated lympathtic tissue ) Peyer patches? M cell related
antigen transporting cells -
M cells endocytose antigens into vesicles - IGA related immunoglobulin A
Peyer’s patches are groupings of lymphoid follicles in the mucus membrane that lines your small intestine. Lymphoid follicles are small organs in your lymphatic system that are similar to lymph nodes. … Peyer’s patches play an important role in immune surveillance of materials within your digestive system
GALT (gut associated lympathtic tissue ) Peyer patches? M cell related
ILEUM
immune surveillance of materials within your digestive system
Monitoring intestinal bacteria populations and preventing the growth of pathogenic bacteria in the intestines.
antigen transporting cells -
M cells endocytose antigens into vesicles - IGA related immunoglobulin A
Peyer’s patches are groupings of lymphoid follicles in the mucus membrane that lines your small intestine. Lymphoid follicles are small organs in your lymphatic system that are similar to lymph nodes. … Peyer’s patches play an important role in immune surveillance of materials within your digestive system
Celiac Disease?
chronic diarrhea, weight loss, gas - can’t absorb gluten - destroys villi and other structures.
Crohn, chronic inflamation
genetic? linear ulcers,
cholera?
bacteria via contaminated food and water,
lactose intolerance
can be acquired later in life. all children ~5 - 7 have tolerance.
2 types of people, lactase persistent, lactase nonpersistent
icteric?
jaundiced
mallory bodies in liver?
keratin intermediate filaments. Hepatic stellate cells secrete collagen in cirrhosis. Liver is from epitheleal cells - hence keratin! and not desmin, vimenten, etc.
Desmin (w/ muscle
Desmin is a myofibrillar protein that is the chief intermediate filament of skeletal and cardiac muscle [40]. It maintains the structural and functional integrity of the myofibrils and functions as a cytoskeletal protein linking Z bands to the plasma membrane.)
Vimenten (mesenchymal cells_ bones, fat, muscle
kuppfer cells?
macrophages of liver
resting parietal cell?
H+, K+, ATPase is sequestered in tubulovesicles. Sounds like this thing is underneath the stomach, and comes out when stretch or stimulated?
When does your stomach release acid?
Acid secretion is stimulated by distension of the stomach and by amino acids present in the food. The intestinal phase: The remaining 10% of acid is secreted when chyme enters the small intestine, and is stimulated by small intestine distension and by amino acids.
Enteroendocrine cells differ from goblet cells re?
Direction they secrete - goblet from apical, entero - release peptides from basal surface, and relesae into blood stream and nearby
both are formed by stem cells in crypts of small and large intestine
both release granules by exocytotic secretion
Does enteric nervous system secrete peptides?
yes, same as enteroendocrine cells
Primary regulator of salivary glands.
Autonomic nervous system
referred pain areas?
gallbladder - right shoulder,
DPH - neck,
stomach - spine near scapula
kidney, groin
appendix, umbilical
Odontoblasts?
Neural crest, make dentin (2nd layer - not enamal, not pulp) Mineralized collagen
Ameloblasts?
enamel - no collagen
pernicious anemia - autoantibodies against parietal - cause no V 12 intrinsic factor -
occurs in main part of stomach FUNDUS - the parietal cells (that was the Q - what part of stomach)
dyspnear, fatigue - would see test with low B12, Schilling test
How does cholera bacteria exert its affect in stomach?
closes chloride channels in enterocyte cell membrane - exit through channels allow sodium and water to leave also - causing dehydration
What is lactase deficiency?
Can’t digest lactose - so undigested lactose is sent to large intestine which causes bloating, pain,
What does lipase do?
breakdown lipid from triglyceride to fatty acid, etc -. triglyc are resynthesized in SER
What does pepsinogin break down in stomach?
proteins and continued in the small intestine via pancreatic juice -
Plica circularis?
permanent fold in small intestine - not in ileum (or not many) gives feathery appearance.
Intestinal villi?
Finger projections of mucosa - covering entire surface, form crypts
Crypts of Lieberkuhn?
Intestinal glands between fingers of villi -
Microvilli of enterocytes ? major amplification of surface
are on top of the villi, and GOBLET cells - simple columnar. Lamina propira surround glands, forms core of villi. Lamina propria has vessels, nerve, lymph, smooth muscle cells -
lamina propria in small intestines? Where does movement come from?
smooth muscle in lamina propria reaching up into each villi
is absorption affected by rhythmic movement?
YES.
What the final layer - serosa covered with?
simple squamous mesothelium
Lacteal?
lymph going up into each lamina propria,
microcirculation of small intestine?
two levels - at microvilla and at villa
What cell is at the base of crypts?
Paneth - stem and enteroendocrin cells also are in the crypts
Jejunum vs ileum
More fat - ileum,
Peyer’s patches?
lymphoid GALT - uptake of antigens antigen presenting cell - ILEUM
In mucosa and some sub
M cells and dendritic cells sample and take up antigens from inteinal lumen - mucosa
Absorptive cells?
enterocytes with their own brush border absorb - brush border contains many many microvilli - with the core of one containing a bundle of 20 - 40 parallel actin filaments
what covers each enterocyte?
glycocalyx and enzymes - lactase, sucrase, etc which breakdown and aborb nutriests
lactose intolerance? genetic defect preventing absorption - what does it caush?
diarrhea - pain
so what two things does brush border do?
Increase surface area - absorb nutrients
what do paneth cells do?
they protect the membranes =, fighting bacteria - they have TNF (tumor necrosis factor), lysozyme, and defensins - they call in dendritic cells to sites of infection, failitating uptake of antigens by forming defensin antigen complexes
M cells and Peyer patches?
M cells overlay peyer patches lymphoid follicles. They have PITS, with lymph and macrophages (antigen presenting cells) . Can endocytose them and transrpot to underlying macrophages and lymphoid cells - where immunie responses are inittiated
CCK?
slows down emptying of stomach by acting on pyloric sphincter.
Stiumulate bile release and secretion of pancreatic enzymes
secretin?
fireman - stim bicarb by pancreatic duct - enahcnes insulin secretion on the islets.
Gastrin in small intesting?
stim HCL in stomach, islet insulin stim,
ups gastric motility and mucosal production
Why chronic diarrhea?
malabsorption of fats, carbs, proteins, etc -
Main causes:
Pancreatic insufficiency -
cystic fibrosis
Celiac disease
four disturbances of diarrhea? and four types (not listed - some continue when fasting, others stop)
not breaking down right,
not digesting at microvilla
not transporting to epithelium where process nutrients
lymph transport problem,
bleeding during diarrhea?
VItamin K deficiency
Diarrhea and cystic fibrosis?
This gene controls the flow of salt and fluids in and out of your cells. If the CFTR gene doesn’t work the way it should, a sticky mucus builds up in your body.
Cystic fibrosis is caused by a change, or mutation, in a gene called CFTR (cystic fibrosis transmembrane conductance regulator).
blocks liver and pancreatic ducts - can’t absorb nutriets lungs thick.
celiac disease?
autoimmune attack against epithelial cells. Killing them
can lactose deficiency be triggered by a virus or bacteria?
yes.
Abetalipoproteinemia?
an inherited disorder - autosomal recessive - that impairs the normal absorption of fats and certain vitamins from the diet. Many of the signs and symptoms of abetalipoproteinemia result from a severe shortage (deficiency) of fat-soluble vitamins (vitamins A, E, and K
signs _ failure to thrive, diarrhea,
can verify via Burr cells in RBCs
Does the large intestine have crypts of lieberkuhn?
YES. tubular glands, smoother surface than in small. goblet cells to lubricate and protect
large intestine job?
absorb water, form fecal mass, make mucus (not only to lubricate but it covers bacteria and particulate matter)
Chagas disease?
Like megacolon, bug destroys intermural neurons in instenstine and heart
diverticulosis vs litis?
outpouching, enhanced by low fiber diet, older people, too much pressure - hernia really right near the mucosal arteries -
ITIS: fever, painful bleeding (vs. no fever, painless bleeding)
Treatment: antibitics, surg - change diet - up water and fiber
Familial Adenomatous Polyposis - PAP?
autosomal dominant - Beta catenin, WNT signaling pathway
POLYPS at 7 - 35 YO, inevitable colon cancer
- advise colectomy before hits.
This disease is supressing the APC tumor suppressor gene.
Three major digestive glands?
Salivary -
Major, minor,
exocrine pancreas (not the islets)
Liver
4 things, lubricate, protect, digest and absorb
saliva contains?
proteins, glycoproteins (mucus), inos, water and Immunoglobulain A
most productive salivary gland?
submandibular (70%) (mucous and serous)- largest is upper palate - parotid (but it doesn’t produce that much)
Paraysmp - water rich saliva,
SYMP - protein rich
Xerostomia ?
Dry mouth - elderly, usually caused by meds - atrophy of oral mucosa
Salivary glands - mucus / serous?
The parotid glands contain nothing but serous cells. The submandibular glands contain both mucous and serous cells. The sublingual glands contain mostly mucous cells with just a few serous cells
Exocrine pancreas?
branched tuuloacinar gland - head to tail
Intercalated ducts of glands?
THEY SECRETE WATER AND BICARB
The intercalated duct, also called intercalary duct (ducts of Boll), is the portion of an exocrine gland leading directly from the acinus to a striated duct. The intercalated duct forms part of the intralobular duct.
Do enzymes pancreas vary based diet?
yes, 20 different kinds, more or less
Acinar ducts produce many! (but see intercalated - are secreting water and bicarb)
Enzyme increased by gastrointestinal hormones CCK and secretin
Does the pancreas have a dual blood supply?
yes, one to acinar ducts,
other to islets (so they can secrete their hormones)
What controls pancreatic enzyme production and release?
Enteroendocrine cells in duodenum, and hormones synthesized in islets
What types of cells is the liver made of?
EPITHELIAL and connective (hence - Keratin intermediate fibers)
Glisson’s capsule?
around the liver
shape of cell of liver
six sided, central vein -
space of Disse Bile canaliculi (canals of Hering)
3 different ways to see liver organiztion
Liver acinus concept best explains patterns of regeneration, matabolic activity, develop of cirrhosis, etc.
Zone 1 - richest in oxygen, nutrients,
What does albumin do?
Albumin is a protein made by your liver. Albumin helps keep fluid in your bloodstream so it doesn’t leak into other tissues. It is also carries various substances throughout your body, including hormones, vitamins, and enzymes. Low albumin levels can indicate a problem with your liver or kidneys.
hepatocyte - two cellular domains
basolateral - absorbs and secrete, faces space of Disse -
apical - BILE border
organization of liver - micro?
sinusoidal passage, on each side are fenestrated epitheleal (can get BLOCKED - ischaemia), space of Disses, hepatocyte
Perisinusoidal cells of ito?
STELLATE cells - preferentially store Vit A , but can turn bad and into fibroid. They can turn into myofibroblasts
found in space of Disse - contain fat - involved in retinoids, reg of blood flow, ECM maintenance but remain QUIESCENT - don’t do much UNLESS Kupffer activate! then become fibrous
What can perisinusoidal cells of ito change into?
collagen producing cells - secrete laminna, growth facts, proteoglycans - and turn into FIBER - cirrhosis of liver
Jobs of liver??
MANY!
degrade ammonia, 50% lympy maintain glucose levels, vitamin D synthesis ketone bodies ACeteacoa), Makes bILE
bile transporters ?
4 kinds - re cholesterol, phospholiips, bilirubin, biliary acid (salts)
What does conjugated bile acid inhibit in small intestin?
growth of bacteria.
What does bile do with Fat?
Helps fat absorption
bilirubin, conjugated, unjugated, who cares?
too much not good - hyperbilirubinemia - will be itchy and yellow - showing that liver isn’t accepting the bilirubin
Gilbert’s syndrome?
autosomal recessive = apparently not a big deal - increased unconjugated bilirubin
deficiency in an enzyme that helps break down bilirubin
Crigler- Najjar is serious!
excessive levels of bilirubin -
type 1 more serious
How does Crigler Najjar affect the circulatory system?
Most bilirubin is eliminated from the body in the feces. When bilirubin levels increase high enough, it can eventually cross the blood-brain barrier, infiltrating brain tissue and causing the neurological symptoms sometimes associated with Crigler-Najjar syndrome.
liver - excessive storage of iron and copper
Wilson’s (copper ) see in eye - kayser fleischer rings
Hereditary hemochormatosis (- increased iron absorption
Is jaundice conjugated or unconjugated bilirubin?
Any bilirubin that manages to become conjugated will be excreted normally, yet it is the unconjugated bilirubin that remains in the blood stream to cause the jaundice. In hepatocellular (or intrahepatic) jaundice, there is dysfunction of the hepatic cells.
Bilirubin levels?
Lower than normal bilirubin levels are usually not a concern. Elevated levels may indicate liver damage or disease. Higher than normal levels of direct bilirubin in your blood may indicate your liver isn’t clearing bilirubin properly. Elevated levels of indirect bilirubin may indicate other problems.
What contracts gallbladder?
CCK from small intestine - which in turn is stimulated by dietary fats
How is cholesterol made soluable?
bile salts and lecithin - more cholesterol or less bile salts - STONE.
where is somatostatin produced?
Pancreas - islets AND it can use the veinous connection of the acinar veins to send somatostatin right away to the acinar group.
Somatostatin from the hypothalamus inhibits the pituitary gland’s secretion of growth hormone and thyroid stimulating hormone. In addition, somatostatin is produced in the pancreas and inhibits the secretion of other pancreatic hormones such as insulin and glucagon.
What does amylase do?
Begin digestion of carbs from the salivary level
What receptors do acinar cells have in pancreas?
CCK and ACh.
What does the pancreas secrete in its ducts?
Enzyme poor alkaline fluid (stim by secretin)
variety of digestive enzymes
What hormones does the pancreas secrete?
somatostatin (inhib HCl)
insulin - decreases blood glucose level
glucagone (gone to camp) elevates glucose levels
Gastrin, PP
Ghrelin
Space of moll?
Liver - collects LYMPH limiting plate of each liver cell ? between vein system and the space of Disse??
What are sinusoidal lining cells?
between sinusoidal liver space and space of Disse - endothelial, no basal lamina
Do hepatocytes directly touch the blood stream?
no, they are guarded by the space of Disse, and epithelial fenestrated cells.
Riley Day?
problem with taste buds
von Ebner is a serous
The von Ebner glands are otherwise known as the serous glands. They are minor glands located near the back of your tongue. One of their roles is to secrete amylase.
What does IgA protect against?
Saliva has it.
Immunoglobulin A (IgA) Immunoglobulin A (IgA) is the first line of defence in the resistance against infection, via inhibiting bacterial and viral adhesion to epithelial cells and by neutralisation of bacterial toxins and virus, both extra- and intracellularly.
Where is the antibody IgA found in the body?
Immunoglobulin A (IgA): It’s found in the linings of the respiratory tract and digestive system, as well as in saliva (spit), tears, and breast milk. Immunoglobulin G (IgG): This is the most common antibody. It’s in blood and other body fluids, and protects against bacterial and viral infections.
Zollinger Ellison Syndrome?
a condition in which a gastrin-secreting tumor or hyperplasia of the islet cells in the pancreas causes overproduction of gastric acid, resulting in recurrent peptic ulcers.
Brunner’s glands
The Brunner glands, which empty into the intestinal glands, secrete an alkaline fluid composed of mucin, which exerts a physiologic anti-acid function by coating the duodenal epithelium, therefore protecting it from the acid chyme of the stomach.
Location: Duodenum
What cells secrete mucus in the stomach?
Foveolar cell. Foveolar cells or surface mucous cells are mucus-producing cells which cover the inside of the stomach, protecting it from the corrosive nature of gastric acid. These cells line the gastric mucosa (mucous neck cells are found in the necks of the gastric pits).
What do neck cells secrete?
Mucous neck cells are found in the upper parts (isthmus and neck) of the gastric glands (SEM). They are smaller than surface mucous cells. They secrete an acidic fluid containing mucin proteins. This differs from the mucus produced by surface mucous cells which is alkaline.
What stimulates histamine secretion in stomach?
ECL cells synthesize and secrete histamine in response to stimulation by the hormones gastrin and pituitary adenylyl cyclase-activating peptide. Gastrin itself is secreted by cells in the epithelium of the stomach, but travels to ECL cells via the blood.
drugs that help with PUD?
Proton pump inhibitors — also called PPIs — reduce stomach acid by blocking the action of the parts of cells that produce acid. These drugs include the prescription and over-the-counter medications omeprazole (Prilosec), lansoprazole (Prevacid), rabeprazole (Aciphex), esomeprazole (Nexium) and pantoprazole (Protonix)
Gliosis?
Gliosis is a nonspecific reactive change of glial cells in response to damage to the central nervous system (CNS). In most cases, gliosis involves the proliferation or hypertrophy of several different types of glial cells, including astrocytes, microglia, and oligodendrocytes.
how many types of astrocytes are there?
- protoplasmic and fibrous - both have GFAP. They can proliferate and form scars
Babinski reflex?
foot reflex when run along center of foot - ALS + hyperreflexia + upper and lower motor neuron loss
two shapes of synatpic - rounded and flat
rounded - inhibitory in general
perineurial 2 functions
elastic protection; blood nerve barrier - actin filaments attached to other cells via tight junctions
epineurium?
collagen bundles, protects, fibroblasts, mast cells
Chromotalosis?
when cytoplasm, nissi body, disappears
neuroma?
swelling at end of area where can’t heal a damaged neuron - pain, missing limb
Intercalculated discs in cardiac muscles?
gap junctions + desmosomes - step looking.
What are von Ebner glands in tongue connected to?
3rd type of tongue - not the fungi or the filiform, the circular - only about 10 or 12 on tongues, can see on tongue. have taste buds
These serous glands open up into the bottom of these circular protusions
Filiform papillae role in tongue
Keritanized - to move food along. no taste buds
Taste bud
has a taste pore pit - mostly on tongue, spindle shaped, various types of cells in the taste bud - mature and immature buds - first 2/3 of tongue links with facial nerve; last 1/3 glossopharyngeal - (just sweet and bitter) - facial all five. Each taste receptor only conveys one of five
Lobe? is it one or several?
Several lobules make a lobe
Bell Palsy?
Facial nerve causing drooping. Surgery re parotoid gland may create this problem.
Parotid? mucus or serous?
SEROUS - almost all. Fluidity plus digestive enzymes and other proteins
ducts ? form in salivary glands? intercalated vs. striated - which is larger?
STRIATED - intercalated feed into striated. mostly see intercalated in parotid -
submandibular gland, mixed or serous?
MIXED -
Striated ducts connect what?
intercalated ducts and excretory ducts. Most developed in submandibular, least developed in sublingual
What synthesizes Iga?
plasma cells in surrounding connective tissue (in the mouth)
Teeth- was forms a protective film over them, called Pellicle?
Mucous cells in salivary glands.
Achalasia in lower esoph - inability of sphincter to relax is associated with absence of what ganglion cells?
Auerbach plexus - will not see normal peristalsis
Cardiac glands in stomach?
produce a neutral mucus in gastric pits.
mucus in the stomach contains what?
bicarb and potassium
Prostiglandins in stomach?
help maintain bicarb secretion by surface mucous cells and increase thickness of surface mucus layer
stem cells in which part of gastric glands?
isthmus - gastric pits above, fundus below
parietal up top in pits, chief below.
acute hemorragic gastritis - caused by ?
alcohol, aspirin -NSAID (nonsteriod antiinflammatory drugs) it inhibits cyclooxygenase causing necrosis of the mucosa - inhitibing production of prosttoglandis
breakdown of mucosal barrier
hormone stimulating gallbladder contraction?
CCK
macrophages and goblet cells are primarily in what part of the gi tract?
lamina propria
Myenteric v auerback?
Auerback DEEPER
1). The myenteric plexus, also known as Auerbach’s plexus, is located between the longitudinal and circular muscle layers of most of the digestive tract. The submucosal plexus, also known as Meissner’s plexus, is situated in the submucosal region between the circular muscle and mucosa.
What does GIP do?
inhibiting hormone of the secretin family of hormones. While it is weak inhibitor of gastric acid secretion, its main role is to stimulate insulin secretion.
Plica circularis.
The inner wall of the small intestine is covered by numerous folds of mucous membrane called plicae circulares. The surface of these folds contains tiny projections called villi and microvilli, which further increase the total area for absorption.
What is pernicious anemia? and how it is caused?
a deficiency in the production of red blood cells through a lack of vitamin B12.
autoimmune gastritis -
Common causes of pernicious anemia include: Weakened stomach lining (atrophic gastritis) An autoimmune condition in which the body’s immune system attacks the actual intrinsic factor protein or the cells in the lining of your stomach that make it.
how does pain change with ulcers and eating?
duodenal - pain goes away - so often will see weight gain because it feels better to eat
How does CCK and secretin regulate pancreatic secretion?
As chyme floods into the small intestine, cholecystokinin is released into blood and binds to receptors on pancreatic acinar cells, ordering them to secrete large quantities of digestive enzymes. Secretin: This hormone is also a product of endocrinocytes located in the epithelium of the proximal small intestine.
CCK - 4 things -
Pancreas - make juices!
Liver - potentiate secretin
Sphinter of ODDI
Contract Gallbladder
Secretin
Liver - MAKE BILE
Pancreas - Release Bicarb
K Cells - GIP
pancrease - insulin - get sugar into blood
What are plasma cells and their function?
Plasma cells can only produce a single kind of antibody in a single class of immunoglobulin. In other words, every B cell is specific to a single antigen, but each cell can produce several thousand matching antibodies per second. This prolific production of antibodies is an integral part of the humoral immune response.
