Nervous and hormonal communication (BIOL5)

Question 1

Features of the nervous system

Answer 1

• Made up of network of cells - neurones:
  
  • Sensory - transmit e- impulses from receptors to CNS
  • Motor - transmit e- impulses from CNS to effectors
  • Relay - transmit e- impulses b/w sensory and motor
• When stimulus detected by receptor cells, impulses sent along a sensory neurone.
  
  • When reaches end, neurotransmitters take info to next neurone
• When impulse reaches end neurone, NT secreted directly onto cells so response’s localised
• NT quickly removed after, so response’s short-lived

Question 2

Hormonal system is made up of glands…

Answer 2

Group cells specialised to secrete substances (hormones)

Question 3

Hormonal system made up of hormones…

Answer 3

Chemical messengers

Question 4

Features of the hormonal system

Answer 4

• Made up of glands and hormones
• Hormones secreted when gland stimulated
  
  • Glands stimulated by chnage in conc
  • Stimulated by impulses
• Hormones diffuse directly into blood, then taken around body by circulatory system
  
  • Diffuse out of blood - hormone bind to spec. receptors
• Communication slower - hormone not released directly onto target cells; travel in blood
• Aren’t b/d quickly as NT - effect lasts longer
• Hormones spread all over - response widespread

Question 5

Features of chemical mediators

Answer 5

• Is chem msgr that acts locally - local response
• Target cells next to where they’re made
• Only travel short distance, so prod. quicker response than hormones
• Examples include histamine and prostaglandins

Question 6

Histamine is a chemical mediator

Answer 6

• Released in response to injury/infection
• Inc. permeability to capillaries to allow cells to move out of blood

Question 7

Prostaglandins are chemical mediators

Answer 7

• Group of chem mediators prod. in most cells
• Involved in inflammation/fever
• Inc. permeability of capillaries