L2 - Homeostasis

Question 1

Walter Bradford Cannon

Answer 1

“staying the same”
Ability of body to maintain stable internal environment despite external changes

Question 2

Tissue level

Answer 2

Tissues repair or replace damaed tissue to restore function.

Question 3

Organism level

Answer 3

Actively regulated by responses of cells tissues and organs through feedback systems

Question 4

Tissue repair

Answer 4

Allows for continued function of tissue
Can occur from cels migrating into the tissue (e.g. fibroblasts from connective tissue)
Can occur from immature (stem) cells within the tissue

Question 5

Epithelial tissue repair

Answer 5

Continual eplacement of epithelial cells in gastrointestinal epithelium and skin
e.g. from stem cells in basal layer
e.g. Hair follicles

Question 6

Connective tissue repair

Answer 6

Some capacity
Bone has continuous capacity for renewal
Fibroblasts can divide and invade damaged tissue for repair
Causes scar tissue

Question 7

Musuclar tissue repair

Answer 7

Limited capacity - from satellite cells in skeletal muscle, not in cardiac

Question 8

Nervous tissue repair

Answer 8

Poor capacity
From stem cells
Supports plasticity

Question 9

Variables to maintain homeostasis

Answer 9

Blood oxygen and carbon dioxide level
Blood glucose concentration
Blood pressure/volume
Blood osmolarity
Ion concentration
Core body temperature (for enzymes)

Question 10

Homeostatic reflex components

Answer 10

Receptor
Control centre
Effectors

Question 11

Homeostatic reflex

Answer 11

1. Receptor detects variable, sends nerve or chemical signal
2. Control centre recieves sensor input, compares set put, and sends output signal
3. Effector recieves signal, responds to adjust the variable (through endocrine or nervous system)

Question 12

Receptors

Answer 12

Chemoreceptor
Thermoreceptor
Mechanoreceptor
Baroreceptor

Question 13

Homeostatic reflex: Core body temp

Answer 13

1. Thermoreceptor recognises drop/increase in temp
2. Control centre sends signal
3. Effectors increase metabolism, shivering, blood vessel constriction OR sweating and blood vessel dilation

Question 14

Homeostatic reflex: Increase blood pressure

Answer 14

1. Baroreceptors detect increase in blood pressure send signal through nervous system (afferent pathways)
2. Control centres signal to different parts of the brain through efferent pathways.
3. Effectors: decrease HR, blood vessels dilate