Lesson 5: Homeostasis Flashcards
Role of glomerulus
Fenestrated capillaries that allows filtrate to be separated from blood.
Role of Bowman’s capsule
Captures filtrate from the glomerulus
Role of proximal convoluted tubule
Site of selective reabsorption
Outline how ultrafiltration works
Blood comes in from the afferent arteriole at high pressure causing molecules to be forced out of the glomerulus. Filtrate is captured by the bowman’s capsule. The proximal convoluted tubule selectively reabsorbs important molecules like glucose and salt.
What are the two sections of the loop of henle and what happens there?
Descending limb - water leaves into the medulla
Ascending limb - Sodium leaves into medulla to maintain high solute concentration.
Where does water reabsorption take place?
Loop of henle and collecting ducts
How does osmoregulation work in the collecting ducts during dehydration?
Hypothalamus senses high solute concentration and triggers the pituitary gland to release ADH.
More aquaporins make its way into the linings of the collecting duct.
Collecting duct becomes more permeable.
More water leaves the filtrate.
What is vasoconstriction?
When blood vessels near the skin surface narrow, reducing blood flow to the skin thus conserving heat.
What is vasodilation?
When blood vessels near the skin surface widen, increasing blood flow to the skin thus releasing heat.
Mechanisms in Regulating Human Body Temperature when it gets too cold.
Vasoconstriction
Shivering
Goosebumps
Mechanisms in Regulating Human Body Temperature when it gets too hot.
Vasodilation
Sweating
Roles of Thermoreceptors and Hypothalamus in Regulating Body Temperature
Thermoreceptors > Hypothalamus > response > adjusted body temp.
What is type 2 diabetes?
Insulin receptors become unresponsive to insulin.
What causes the pancreas to not be able to produce insulin?
Betacells of the pancreas are destroyed by one’s own immune system.
What is type 1 diabetes?
The inability of the pancreas to produce insulin.
Explain how blood glucose levels are regulated if it gets too high.
Receptors detect the increase.
Beta cells (β) in the pancreas secrete insulin. Insulin opens glucose channels for uptake.
Glucose gets converted into glycogen in the liver.
Explain how blood glucose levels are regulated if it gets too low.
alpha cells secrete glucagon.
Glycogen hydrolysed into glucose.
