PSYCHOBIOLOGY - neurons

Question 1

3 reasons that complex organisms require a nervous system

Answer 1

• cells inside body not in direct contact with outside world
• cells live in diff environments but are interdependent for survival
• cells have become specialised

Question 2

what are nerve impulses for?

Answer 2

constant & rapid communication between cells, controlling & adjusting ongoing activity

Question 3

endocrine system function

Answer 3

• secretes hormones into the blood
• provides slow coordination

Question 4

nervous system function

Answer 4

• transmits electrical impulses between 2 or more cells
• fast & precise coordination

Question 5

state 2 functions of neurons

Answer 5

• generate & transmit electrical impulses
• integrate cellular input to modulate electrical activity

Question 6

describe the importance of generation & transmission of electrical impulses via neurons

Answer 6

• impulses reach specific targets & modifies the target cell
• rapid, over great distance
• point to point - specific
• allows selective control of specific structures

Question 7

describe the importance of neurons integrating cellular input to modulate electrical activity

Answer 7

• input is used to adjust output
• diff sources signals are combined
• communication is structured

Question 8

what is the general form of a neuron?

Answer 8

cell body with long extensions away from it

Question 9

describe the special requirement of neurons

Answer 9

no possibility to store energy
- glucose & oxygen must be constantly supplied
- otherwise neurons stop working in secs & die within mins

Question 10

describe the life span of a neuron

Answer 10

• they develop from neural stem cells
• neurogenesis almost complete 5 months after conception & after this, dead neurons not usually replaced
• 20-80% of all neurons die during maturation

Question 11

what are glia cells?

Answer 11

• develop from neural stem cells
• provides protected environment for neurons to survive
• as many glia as neurons in brain
• 1/10 size of a neuron

Question 12

name the 3 types of glia cell

Answer 12

astrocytes
microglia
oligodendroglia

Question 13

describe astrocytes

Answer 13

• star shaped
• transports nutrients from blood vessels to neurons & waste away
• holds neurons in place
• part of neuron signalling

Question 14

describe microglia

Answer 14

• small
• mobile for defensive function
• produce chemicals which aid repair of damaged neurons & digest dead neurons in phagocytosis

Question 15

describe oligodendroglia

Answer 15

• large, flat branches wrapping around axons
• consist of myelin sheath