Homeostasis

Question 1

What is homeostasis?

Answer 1

• ability for an organism to maintain its internal environment despite changes to its internal or external environment

Question 2

What happens when homeostasis is disturbed? What are examples of disturbances?

Answer 2

• disease
• aging, genetic mutations, pathogens, environmental factors, trauma

Question 3

What are intrinsic factor that effect homeostasis? Extrinsic factors?

Answer 3

• intrinsic: internal/existing conditions
• extrinsic: environmental factors

Question 4

What are the 5 sensory receptors that help maintain homeostasis?

Answer 4

• mechanoreceptors: pressure
• thermoreceptors: temp
• electromagnetic receptors: light
• nocireceptors: pain
• chemoreceptors: blood composition

Question 5

Neuronal response is mediated by signaling: ________ & ________

Answer 5

• neurotransmitters: chemicals released by neurons that diffuse across a small gap to adjacent neurons
• neurohormones: chemicals released by neurons into blood for action at a distant target organ

Question 6

Up-regulation makes receptors ______ sensitive to a hormone when levels are _______

Down-regulation makes receptors ______ sensitive to a hormone when levels are _______

Answer 6

• more, low. Absence of a hormone triggers a increase in receptors
• less, high. Presence of a hormone triggers a decrease in receptors

Question 7

T/F: negative feedback allows a body to amplify a change

Answer 7

• false
• negative feedback activates mechanisms to reverse change, ex: sweating to lower body temp (most common)
• positive feedback results in a greater change in the same direction,self amplifying, ex: birth or blood clotting