Lecture 5 Flashcards
_____________neurons store,
& secrete hormones made by the brain
Neurosecretion:
Precursor hormone that is converted to an active hormone in another tissue or cell.
– Usually _______
has no effects or weaker effects
What Extends to protein hormones
pro hormones
Extend to protein hormones
– Weaker variant ready to go inside the source cell
– A large peptide/protein precursor then cleaved to form
a shorter active peptide.
– If there are two steps, then pre-pro-hormone àprohormone
àactive hormone.
How does the endocrine system reduce the
action of a hormone in a tissue or cell?
• Inactivate or metabolize the hormone in the target cell/tissue
- Convert to inactive form (e.g. T4àrT3, cortisolàcortisone)
• Sequester the hormone in the blood so it cannot interact with a receptor
- e.g. CBG, SHBG, TBG
• Actively transport the hormone out of the cell or tissue
- e.g. MDRpG (multiple drug resistance P-glycoprotein), MCT and LAT thyroid
hormone transporters
• Do not express the receptors
_____________also called islands of Langerhans, irregularly shaped patches of endocrine tissue located within the pancreas of most vertebrates
Islets of Langerhans
________________: insulin and glucagon
both have pro hormones
Beta cells: _________
insulin
alpha cells:_______________
glucagon
Where is glucose coming from
-Digestion:
______________: sugar from dietary
source
Digestion:
Glycogenolysis:
Gluconeogenesis:
_____________ Liver mobilizes
glucose stored as glycogen
Glycogenolysis:
\_\_\_\_\_\_\_\_\_\_\_\_\_ Liver turns to alternate sources (fat & muscle)
Gluconeogenesis:
What factors increase blood glucose
- glucose absorption from digestive tract
- glyconlysis of glycogen
- through glujconeogensis
What factors decrease blood glucose
- transport glucose into cells
- for storage: glycogenesis
- storage as triglycerides
- urinary excretion of glucose
_________- mobilizing glucose from glycogen
Glycogenolysis
__________ - alternate sources of glucose
Gluconeogenesis
_________– storing glucose as glycogen
Glycogenesis
___________ - Reversible storage of glucose as glycogen, a branched glucose polymer.
Stored in many organs, primarily liver (and skeletal muscle)àdecreases blood
glucose
Glycogenesis
__________ - glucose monomers are removed from glycogen branches via
phosphorolysis, by glycogen phosphorylaseàincreases blood glucose
Glycogenolysis
___________________ - gluco = glucose, neo = new, genesis = production; The
conversion of two pyruvate molecules into glucose àincreases blood
glucose
Gluconeogenesis uses pyruvate from fat/muscle to replenish hepatic
glycogen stores which is then used to maintain blood glucose levels
Gluconeogenesis
____________ - glyco = glucose, lysis = splitting; splits glucose into two pyruvate
molecules àdecreases blood glucose
Glycolysis
_______________
• Energy independent
• Allow transport across membrane along
concentration gradient
Facultative glucose transporters (GLUTs)
_______________
• Energy dependent (indirectly)
• Kidney and intestine
Sodium-glucose transporters (SGLTs)
