Respone to stimuli

Question 1

Can you define a stimulus and a response

Answer 1

A stimulus is a change in the internal or external environment

A coordinator formulatess a suitable response

Question 2

Can you explain how each type of response increases an organism’s chances of survival?

Answer 2

Organisms must respond to changes in their environment in order to survive

They can only survive if they are successful at:

Finding favourable conditions for living

Finding food

Avoiding being eaten

If these vital requirements are not met then a species will die out or go extinct

Question 3

Can you describe taxis, kineses, and tropisms?

Answer 3

Taxis is directional and active whilst kinesis is random

Tropisms is the general phenomenon of directed growth and deformation in response to stimuli

Question 4

Can you describe the stimuli that plants respond to?

Answer 4

Hydrotropismis growth in response to water.

Geotropismis growth in response to gravity.

Phototropismis growth is response to light.

Question 5

Can you describe plant growth factors such as IAA ?

Answer 5

IAA is the main auxin in plants,regulating growth and developmental processes such as cell division and elongation, tissue differentiation, apical dominance, and responses to light, gravity, and pathogens

Question 6

Can you explain phototropism in flowering plants ?

Answer 6

Phototropism isthe ability of the plant to re-orient the shoot growth towards a direction of light source

Question 7

Can you explain how a simple reflex arc works ?

Answer 7

Sensory neuron sends electrical impulses to a relay neuron, which is located in the spinal cord of the CNS.

Question 8

Can you explain the roles of sensory, intermediate and motor neurones play in a reflex arc ?

Answer 8

Relay neurons connect sensory neurons to motor neurons. Motor neuron sends electrical impulses to an effector. Effector produces a response

Question 9

Can you outline the importance of reflex arcs ?

Answer 9

The Reflex Arc is important because itprovides a quick and automatic response to potentially harmful stimuli, allowing the body to quickly protect itself

Question 10

Can you describe the main features of a sensory reception ?

Answer 10

convert the information to a form that the human body can interpret.

Question 11

Can you describe the structure of a Pacinian corpuscule and explain how it works

Answer 11

The structure of Pacinian Corpuscles isintricate, consisting of layers of connective tissue separated by a gel-like substance called lamellae

Question 12

Can you describe how receptors work in the eye ?

Answer 12

Photoreceptors work by absorbing photons of light and triggering chemical and electrical changes in the cell, which then triggers a nerve impulse that is sent to the brain.

Question 13

Can you describe the autonomic nervous system ?

Answer 13

The autonomic nervous system isa component of the peripheral nervous system that regulates involuntary physiologic processes including heart rate, blood pressure, respiration, digestion, and sexual arousal

Question 14

Can you explain how the autonomic nervous system controls heart rate ?

Answer 14

Two nerves connected to the medulla regulate heart rate by either speeding it up or slowing it down: The sympathetic nerve releases the neurotransmitter noradrenaline to increase heart rate

Question 15

Can you explain the role chemical and pressure receptors play in the processes controlling the heart rate ?

Answer 15

Two types of receptors,baroreceptors(pressure receptors) and chemoreceptors (chemical receptors) areresponsible for detecting stimuli in the blood and signalling to the medulla oblongata to modify our heart rate