Co-ordination and Response in Humans Flashcards
what is the central nervous system made up of?
the central nervous system consists of the brain and the spinal cord
what is a sensory neurone?
transmits nerve impulses from the sense organs or receptors to the central nervous system
what is a relay neurone?
transmits nerve impulses from the sensory neurone to the motor neurone.
where is a relay neurone found?
they are found within the central nervous system
what is a motor neurone?
transmits nerve impulses from the central nervous system to the effectors
how does a nerve impulse get transmitted from a neurone to another neurone?
nerve impulses are transmitted across a synapse via neurotransmitters from the (___ neurone) to the (___ neurone)
what is the reflex action?
it is a involuntary action, an immediate response to a specific stimulus without conscious control
what is the reflex arc?
a reflex arc is the shortest pathway which nerve impulses travel from the receptor to the effector in a reflex action
describe the pathway taken when a person moves his arm reflectively away from a source of pain.
- [receptors] in the skin detect the** [pain >stimulus],** and a nerve impulse is generated
- the nerve impulse impulse is transmitted by a [sensory] neurone to the spinal cord to a** [relay]** neurone via neurotransmitters across a synapse
- the relay neurone transmits the nerve impulse to a [motor] neurone via neurotransmitters across a synapse
- the motor neurone transmits the nerve impulse to an [effector>arm muscle] via the ventral root
- the muscle **[reaction>contracts **]and moves the arm away
S,R,S,R,M,E,R
what is the choroid?
contains a lot of blood capillaries, supplies nutrients to cells in the eye
- there is a layer of pigment(melanin) between the retina and choroid that absorbs light, to prevent reflection of light within the eye.
function of the cornea?
it refracts or bend light rays into the eye
what are the 2 kinds of photoreceptors in the retina?
rod cells and cone cells
what are rod cells?
rod cells are photoreceptors in the retina, that detect light (black and white visions)
- they are present throughout the retina EXCEPT the fovea and the blind spot
what are cone cells?
cone cells are photoreceptors in the retina, that detect light (red/green/blue)
- present at highest concentration at the fovea, absent at the blind spot
pupillary reflex (when it is bright, what happens to the eye?)
Circular muscles of the iris > contracts
Radial muscles of the iris> relax
pupils> constrict
amount of light entering the eye> reduced
pupillary reflex (when it is Dim, what happens to the eye?)
Circular muscles of the iris > relax
Radial muscles of the iris> contract
pupils> dilates
amount of light entering the eye> increase
Accommodation reflex (when object of near to the eye)
Ciliary muscle>Contract
suspensory ligaments> slacken
lens> More convex
focal length> Shorten
Accommodation reflex (when object of far from the eye)
Ciliary muscle>relax
suspensory ligaments> taut
lens> less convex
focal length> increase
what is a endocrine system?
it is made up of endocrine glands throughout the body which secrete hormones into the blood stream .
hormones will have various effects on their target organs
state 4 endocrine glands in the body
Pancreas, adrenal glands, gonads(testes in males, ovaries in females), pituitary glands
What is an endocrine gland?
A group of cells of organ that secretes hormones
What is a hormone?
A hormone is a chemical messenger, secreted by the endocrine glands into the blood. Hormones travel via the blood to target organs to exert their effects.
how are hormones broken down?
Hormones are broken down in the liver after use, and excreted through the kidneys
(e) define a hormone as a chemical substance, produced by a gland, carried by the blood, which alters the
activity of one or more specific target organs and is then destroyed by the liver
(f) state what is meant by an endocrine gland, with reference to the islets of Langerhans in the pancreas
(g) outline how the blood glucose concentration is regulated by insulin and glucagon
What are the 2 kinds of hormones?
Peptide and steroid
Peptide hormones> insulin and glucagon
Steroid hormones> sex hormones
What happens after a hormone is sent to their target organs?
When hormones reach the target organ, they bind to receptors on cells.
The cells will respond to the hormone by changing their metabolic activity
Describe what happens when the blood glucose level in the body is below normal?
(Stimulus) Blood glucose level below normal,
(Receptor) prancreas detects changes in the blood glucose level
(Effector) Islets of Langerhans in the pancreas secretes glucagon
(Effect on target organs) Liver and muscle cells are stimulated to increase conversion of glycogen to glucose. Stimulating the liver to release glucose into the blood.
Blood glucose returns to normal
Describe what happens when the blood glucose level in the body is above normal?
(Stimulus) Blood glucose level above normal,
(Receptor) prancreas detects changes in the blood glucose level
(Effector) Islets of Langerhans in the pancreas secretes insulin
(Effect on target organs) Liver and muscle cells are stimulated to increase uptake of glucose from blood, and increase the conversion of excess glucose to glycogen for storage.
Blood glucose returns to normal
What are the effects of adrenaline?
- increase metabolic rate
- increase heart rate and depth of ventilation
- causes the pupils to dilate
- increase blood pressure
What is type 1 diabetes
It is genetic, person lacks insulin production
