DLA 6 lecture 9+10

Question 1

Large bowel obstruction

Answer 1

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

Question 2

nerve of levator ani?

Answer 2

sacral plexus

Question 3

internal anal sphincter

PSNS vs SNS

Answer 3

SNS = constricted

PSNS = relaxed

Question 4

nerve of external anal sphincter

Answer 4

inferior rectal nerve (branch of pudendal)

Question 5

anal column above vs below pectinate line?

tissue origin and nerve type?

Answer 5

above:
endodermal origin
visceral afferent nerves

below:
ectodermal origin
somatic afferent nerves

Question 6

internal rectal venous plexus vs external rectal venous plexus?

Answer 6

internal rectal venous plexus also known as internal hemorrhoidal veins

Lead to painless hemorrhoids

external rectal venous complex or external hemorrhoidal veins

painful hemorrhoids

Question 7

blood supply of rectum and anal canal

Answer 7

superior, middle, and inferior rectal arteries

superior = inferior mesenteric 
middle = internal illiac 
inferior = internal pudendal

Question 8

Hematochezia

Answer 8

the passage of fresh blood per the anus, usually in or with stool

Question 9

lymphatics above and below the pectinate line?

Answer 9

above:
internal illiac nodes

below:
superficial horizontal inguinal nodes

Question 10

Diverticulosis

Answer 10

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

Question 11

complication of diverticulosis

Answer 11

Diverticulitis

Obstruction of the diverticulum leading to infection. If rupture occurs it may lead to peritonitis /fistula formation

Question 12

sigmoid volvulus

Answer 12

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

Question 13

radiological of sigmoid volvulus

Answer 13

double loop obstruction
coffee bean sign
no gas is seen

Question 14

clinic significance of the Left supraclavicular node (Virchow’s node)

Answer 14

can be seen during physical examination

due to distant metastasis from abdominal organs

Question 15

internal vs external hemorrhoids

Answer 15

internal:
prolapse of the rectal mucosa
contains dilated veins of the internal rectal plexus

external:
dilations of the external rectal plexus

Question 16

portal hypertension?

Answer 16

The portocaval anastomoses between the superior , middle, and inferior rectal veins become varicosed

Question 17

lymph drainage of the stomach and duodenum

Answer 17

celiac group

Question 18

how is hepatic glucokinase regulated?

Answer 18

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

Question 19

How is PFK-1 regulated?

Answer 19

normal ATP levels inhibit PFK-1

this inhibition is overcome by AMP and fructose 2,6 bis-P

Question 20

how is hepatic pyruvate kinase regulated?

Answer 20

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

Question 21

when is glycolysis favored

Answer 21

high insulin!

PFK-2 is active and forms fructose 2,6-Bis-P

PFK-1 is active and BPase-2 is inhibited

Question 22

when is gluconeogenesis favored?

Answer 22

high glucagon

PFK-2 is phosphorylated and inhibited

Bpase-2 is active and degrades fructose 2,6-Bis-P

PFK-1 is also inhibited

Question 23

glycogen synthesis

Answer 23

activated by insulin

glycogen synthase is dephosphorylated and active

glycogen phosphorylase kinase is dephosphorylated and inactive

Question 24

glycogen degradation

Answer 24

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

Question 25

role of glycogen phosphorylase

Answer 25

generates glucose 1-P using inorganic phosphate

Glucose 1-P is converted to Glucose 6-P and used for glycolysis

Question 26

glycogen synthase

Answer 26

activated by dephosphorylation
inactivated by PKA

allosterically activated by glucose-6-P

Question 27

glycogen phosphorylase

Answer 27

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

Question 28

how is glycogen synthesized

Answer 28

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

Question 29

How is glycogen broken down??

Answer 29

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

Question 30

MODY-2

Answer 30

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

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