Flashcards in Repro & Endocrine Deck (74)
The penile urethra sits within which muscle?
What is the name of the plexus taking away blood from the testes?
Where is each lobe of the pancreas located in the dog?
Left=within deep leaf of greater omentum
Which cells exist within islets of Langerhans in the pancreas?
Alpha and beta cells
How are exocrine cells arranged in the pancreas?
What about endocrine cells?
Exocrine=clusters called acini
Endocrine=islets of Langerhans
In the pancreas, what do acini produce?
Digestive enzymes that flow through ducts into the GI tract
Give 3 other catabolic hormones besides glucagon
What is the difference between type 1 and type 2 diabetes?
Type 1=inadequate insulin secretion
Type 2=abnormal target cell responsiveness
How does glucose enter cells?
Is this an active or passive process?
Through GLUT transporters
Passive (concentration gradient)
How does insulin increase glucose uptake in skeletal muscle, adipocytes and other cells?
Signals the cell to inset GLUT4 transporters into the membrane, allowing glucose to enter
What are the 3 things glucose can be converted to?
How is glucose taken up into hepatocytes?
Glucose enters the cell using GLUT2 transporters.
Insulin stimulates hexokinase to maintain a low intracellular concentration of glucose (converts glucose to glucose 6-phosphate)
What is the difference between presence of transporters in the membranes of hepatocytes compared with skeletal muscle, adipocytes and other cells?
Hepatocytes: GLUT2 transporters are ALWAYS present in the cell membrane (not insulin-dependant), transport in both directions.
Skeletal muscle cells: GLUT4 transporters are only present in the cell membrane when insulin signals the cell to insert them there. Only allow glucose to enter, not leave.
Are neurones sensitive to insulin?
How does excess glucose in the CSF affect neurones in the CNS?
Increases osmolarity of CSF, drawing water out of neurones
How does insulin decrease blood concentrations of glucose?
Increasing glycogen synthesis
Decreasing hepatic glycogenolysis
Increasing glucose transport into skeletal muscle cellls and adipocytes through GLUT4 transporters
What effect does insulin have on protein metabolism?
Increases protein synthesis and uptake of amino acids
What effect does insulin have on fat metabolism?
Increases fat synthesis and decreases lipolysis
What effect does insulin have on K+?
Increases uptake of K+ into skeletal muscle and fat cells by providing ATP to activate the NA+/K+ ATPase pump
Describe the structure of insulin and discuss species similarities
Insulin=2 peptides joined by a disulphide bridge.
Porcine and canine insulin molecules are identical, and only differ from human insulin by a single amino acid.
Feline and bovine insulin are similar in structure.
What kind of receptors does insulin bind to?
Tyrosine kinase membrane receptors
What is the plasma half-life of insulin?
What about biological half-life?
Plasma= 5-10 mins
In which species is the bulbourethral gland absent?
Sexual maturity is signalled by what?
Increased GnRH pulsatility
Where is insulin metabolised?
Liver and kidney
Which form of lente insulin has the longer duration?
What is the average duration of a soluble insulin formulation?
What about non-soluble?
What is meant by postprandial?
eg postprandial hyperglycaemia
Give 2 adverse effects of using exogenous insulin?
Insulin resistance (due to stress, insulin antibodies, or insulin receptor desensitisation)