Unit 5: Responding to the Environment Flashcards
How do the receptors communicate with the effectors? (2 marks)
1) via the Nervous System
2) via the Hormonal System
Describe the 3 types of NEURONES found in the NERVOUS SYSTEM and their roles:
Sheril Mathew Really?
1) Sensory Neurones - transmit ELECTRICAL IMPULSES from receptors —> CNS
2) Motor Neurones - transmit ELECTRICAL IMPULSES from CNS —> Effectors
3) Relay Neurones - transmit ELECTRICAL IMPULSES between Sensory and Motor Neurones
Describe the entire pathway from when a stimulus is detected to the effector: (6 KEY words)
Stimulus
detected by RECEPTOR cells
electrical impulse sent along SENSORY neurone
chemicals called NEUROTRANSMITTERS take info to the next neurone
the CNS processes this information
impulse sent along MOTOR neurone
to the EFFECTOR
Nervous System Communication is… (3 marks)
LISA SIMPSON ROCKZZZ
- Localised
- Short Lived
- Rapid
Hormonal System Communication is… (3 marks)
- Wide Spread
- Long Lasting
- Slower
Define “Gland”:
a group of CELLS that are specialised to SECRETE a useful substance such as a hormone
e.g. pancreas secretes insuilin
What two factors can stimulate Glands?
1) Change in the CONCENTRATION of another substance e.g. a hormone
2) Electrical Impulses
Which receptors detect PRESSURE in your skin?
Pacinian Corpuscles
the SENSORY NERVE ENDINGS in Pacinian Corpuscles is wrapped around __________ called ________ ?
CONNECTIVE TISSUE
LAMELLAE
What happens when a Pacinian Corpuscle is stimulated?
the LAMELLAE are DEFORMED and PRESS on the SENSORY NERVE ENDING
the deformation of Pacinian Corpuscles’ Lamellae has a knock-on effect, which is…?
deformation of STRETCH-MEDIATED (so DAAAAAYUM) SODIUM CHANNELS
what happens when the STRETCH-MEDIATED SODIUM CHANNELS become deformed? (4 marks)
the SODIUM ion channels OPEN
Sodium ions DIFFUSE into the cell
creating a GENERATOR POTENTIAL
if this generator potential reaches the THRESHOLD, it triggers an ACTION POTENTIAL
What are LIGHT RECEPTORS in your EYE called? And where are they contained?
Photoreceptors
within the RETINA
What is the FOVEA?
an area of the RETINA where there are lots of PHOTORECEPTORS
Purpose of the Optic Nerve?
carries NERVE IMPULSES from the Photoreceptor cells in the Retina ———-> the BRAIN
What is the “Blind Spot”?
where the optic nerve leaves the eye - so there are no photoreceptor cells so it’s not sensitive to light
What are the two types of photoreceptor cells?
RODS and CONES
Where are the rods found and what’s the pigment present?
- in the PERIPHERAL parts of the retina
- rhodopsin
Where are the cones found and each cone ________ with ___ bipolar cell
packed together in the fovea
- synapses
- ONE
3 factors that affect the SPEED of CONDUCTION of Action Potentials?
1) Myelination
2) Axon Diameter
3) Temperature
What is a synapse?
What’s a synaptic cleft?
1) a JUNCTION between a NEURONE and the NEXT CELL
2) tiny gap between cells at a synapse
What is the voltage across the MEMBRANE at Resting Potential?
-70 mV
What is the “Refractory Period” (3 marks)
the refractory period acts as a TIME DELAY between one action potential and the next
so, the refractory period ensures ACTION POTENTIALS don’t overlap, but pass along as DISCRETE IMPULSES
this also makes action potentials UNIDIRECTIONAL
What is meant by “Action Potentials have an ALL or NOTHING nature?” (3 marks)
once the THRESHOLD is reached, an action potential will always fire with the SAME CHANGE IN VOLTAGE.
If threshold ISN’T reached, Action Potential won’t fire
the bigger the STIMULUS, action potentials are fired more FREQUENTLY
