B9- Coordination and response Flashcards
Define Hormone
-A chemical substance,
-produced by a gland
-carried by the blood,
-alters the activity of one +specific target organs
Describe adrenaline
The hormone secreted in ‘fight or flight’ situations.
Name some effects of adrenaline
- Increased pulse rate
- Increased breathing depth and rate
- Pupil dilation
- Increase blood glucose concentration
Why is the blood glucose concentration increased when adrenaline is secreted?
- To provide energy to the muscles for respiration for ‘fight or flight’
What is a nerve impulse?
An electrical signal
that passes along nerve cells called neurones
Describe a voluntary action
An action made by the brain, conscious
Describe an involuntrary action
An automatic response made without conscious decisions
What is the order of an arc reflex?
Receptor, sensory neuron, relay neuron, motor neuron and effector
Describe a reflex action
Automatically and rapidly integrating and coordinating stimuli with the responses of
effectors (muscles and glands)
What is the function of the cornea?
Refracts light
What is the function of the Iris?
controls how much light enters the pupil
What is the function of the retina?
Contains light receptors, some sensitive to light of different colours.
What is the function of the optic nerve?
carries impulses to the brain
Define homeostasis
The maintenance of a
constant internal environment
How do the muscles make the pupil smaller? (circular + radial)
Circular muscles- contract
Radial muscles - relax
More adrenaline is produced by the adrenal gland when a person is frightened. Blood glucose concentration decreases when adrenaline is secreted. True or false?
False
Blood glucose concentration increases to provide energy to muscles for respiration
Is the change in pupil size due to light intensity voluntary or involuntary?
Involuntary
The lens in the eye changes shape during accommodation.
Voluntary or Involuntary?
Voluntary
In a plant shoot, where is auxin made and what is its effect? [2]
Shoot tip
Promotes cell elongation
When the environment is too hot what happens to the arterioles?
They vasodilate
In vasodilation to reduce temperature and to allow radiation
Where is the blind spot found in the eye?
In the retina, in front of the optic nerve
A person changes their focus from a near object to a distant object.
Describe the changes in terms of the ciliary muscle, suspensory ligaments and the lens.
Ciliary muscle- relax
Suspensory ligaments- contract/tighten
Lens- becomes tall and thin
Explain the importance of the pupil reflex
To protect the eye from being blinded by bright light
State the name of the hormone released to reduce the glucose levels in the blood
Insulin
Suggest one way that the blood glucose concentration could be reduced other than by insulin
Exersice
Describe how the liver and pancreas work together to cause changes in blood glucose levels. [3]
- Pancreas releases glucagon
- Glycogen (stored) in liver
- Glycogen converted to glucose
State a term that can be used to describe the control of blood glucose concentration.
Negative feedback
State 3 differences between the hormonal and nervous systems.
Hormonal- chemical hormones, slow information transfer time, long-lasting action
Nervous- Electrical impulses, very fast information transfer time, short-lived action
Describe how adrenaline is transported.
Through the blood
