DLA 6 lecture 9+10 Flashcards
Large bowel obstruction
tends to be located in periphery
increased intra-luminal gas
presence of haustra
clinical: nausea and vomiting abdominal distension increased bowel sounds no passage of gas
nerve of levator ani?
sacral plexus
internal anal sphincter
PSNS vs SNS
SNS = constricted
PSNS = relaxed
nerve of external anal sphincter
inferior rectal nerve (branch of pudendal)
anal column above vs below pectinate line?
tissue origin and nerve type?
above:
endodermal origin
visceral afferent nerves
below:
ectodermal origin
somatic afferent nerves
internal rectal venous plexus vs external rectal venous plexus?
internal rectal venous plexus also known as internal hemorrhoidal veins
Lead to painless hemorrhoids
external rectal venous complex or external hemorrhoidal veins
painful hemorrhoids
blood supply of rectum and anal canal
superior, middle, and inferior rectal arteries
superior = inferior mesenteric middle = internal illiac inferior = internal pudendal
Hematochezia
the passage of fresh blood per the anus, usually in or with stool
lymphatics above and below the pectinate line?
above:
internal illiac nodes
below:
superficial horizontal inguinal nodes
Diverticulosis
Outpouching of colonic mucosa and submucosa
that herniate through muscular layer. Generally
found in the sigmoid colon
may erode into colonic vessels; leading to bleeding
may be asymptomatic and have painless rectal bleeding
labs:
anemia or positive stool guaiac test
radiology:
diverticular seen
clinical: left lower pain abdominal tenderness fever abdominal distension
complication of diverticulosis
Diverticulitis
Obstruction of the diverticulum leading to infection. If rupture occurs it may lead to peritonitis /fistula formation
sigmoid volvulus
A twisting of the sigmoid colon around it mesentery.. leading to an obstruction
clinical:
abdominal pain
nausea and vomiting
history of constipation
complications:
colonic ischemia
colonic perforation
peritonitis
radiological of sigmoid volvulus
double loop obstruction
coffee bean sign
no gas is seen
clinic significance of the Left supraclavicular node (Virchow’s node)
can be seen during physical examination
due to distant metastasis from abdominal organs
internal vs external hemorrhoids
internal:
prolapse of the rectal mucosa
contains dilated veins of the internal rectal plexus
external:
dilations of the external rectal plexus
portal hypertension?
The portocaval anastomoses between the superior , middle, and inferior rectal veins become varicosed
lymph drainage of the stomach and duodenum
celiac group
how is hepatic glucokinase regulated?
glucokinase is active when in the cytosol and is not product inhibited
The hepatic glucokinase regulatory protein (GKRP) translocates glucokinase into the nucleus at low glucose levels or high fructose 6-P
How is PFK-1 regulated?
normal ATP levels inhibit PFK-1
this inhibition is overcome by AMP and fructose 2,6 bis-P
how is hepatic pyruvate kinase regulated?
at high levels of glucose, PK is allosterically activated by fructose 1,6-bis-P which overcomes the ATP inhibition
at low levels of glucose glucagon leads to the phosphorylation of PK which inhibits it along with alanine
phosphorylated by PKA
when is glycolysis favored
high insulin!
PFK-2 is active and forms fructose 2,6-Bis-P
PFK-1 is active and BPase-2 is inhibited
when is gluconeogenesis favored?
high glucagon
PFK-2 is phosphorylated and inhibited
Bpase-2 is active and degrades fructose 2,6-Bis-P
PFK-1 is also inhibited
glycogen synthesis
activated by insulin
glycogen synthase is dephosphorylated and active
glycogen phosphorylase kinase is dephosphorylated and inactive
glycogen degradation
activated by glucagon and epinephrine
glycogen synthase is phosphorylated by PKA and inactive
Glycogen phosphorylase kinase is phosphorylated
GPK phosphorylates glycogen phosphorylase
calcium partially activates GPK, fully activated after phosphorylation
epinephrine optimizes this process
role of glycogen phosphorylase
generates glucose 1-P using inorganic phosphate
Glucose 1-P is converted to Glucose 6-P and used for glycolysis
glycogen synthase
activated by dephosphorylation
inactivated by PKA
allosterically activated by glucose-6-P
glycogen phosphorylase
activated by phosphorylation by GPK
allosterically inactivated by glucose-6-P and ATP and free glucose
can be activated in muscle by AMP in extreme muscle contraction
how is glycogen synthesized
glycogen synthase uses UDP-glucose and needs a primer (glycogen)
glycogenin is used for de-novo synthesis. glycosylates its own tyrosine residue
will form alpha 1,4 linkages and branching enzyme will form alpha 1,6 linkages
a 4:6 transferase can cleave a 1,4 chain and link it to a 1,6 chain to form granule
How is glycogen broken down??
glycogen phosphorylase cleaves alpha 1,4 bonds of glycogen to glucose 1-P
the enzyme needs PLP and inorganic phosphate
first enzyme is 4:4 transferase which cleaves alpha 1,4 bonds closest to the branch point
the alpha 1,6 glucoside cleaves alpha 1,6 bonds
MODY-2
deficiency of glucokinase
impaired insulin secretion from beta cells
due to deficiency a higher blood glucose level is needed for insulin release
patient will have mild fasting hyperglycemia with normal weight and no metabolic syndrome
auto dominant
