4.5 Response and Regulation Flashcards
What is the function of the nervous system?
transmits signals between different parts of the body
How is information sent through the nervous system?
As a series of small electrical signals
What are the sense organs for the following stimulus: light sound temperature touch chemicals
eyes ears skin skin tongue/nose
What is a receptor?
a group of specialised cells that detects a stimulus
What is a reflex?
a fast, automatic response to a stimulus
What is the function of a reflex action?
protect the body
Name the 3 neurones that are involved in a reflex arc
sensory neurone
relay neurone
motor neurone
What is a reflex arc?
the nerve pathway that makes such an automatic response possible
What is the central nervous system made up of?
spinal cord and brain
EXAM STYLE
Each reflex reaction follows a series of steps
What is the order to show the nerve pathway of a reflex arc? (potential 6 marker)
STIMULUS is picked up by a RECEPTOR which transmits an electrical impulse to a SENSORY NEURONE
SENSORY NEURONE passes the electrical impulse to the RELAY NEURONE in the SPINAL CORD via a SYNAPSE
RELAY NEURONE passes the electrical impulse on to a MOTOR NEURONE
which carries the response back to the effector organ
the response is carried out by the effector organ e.g muscle contracts
What does sense organ mean?
an organ that has receptors sensitive to a particular kind of stimulus
What are the 3 properties of a reflex action?
fast
automatic
protective
Explain what happens to hairs when we are cold?
The hair erector muscle contracts which cause the hair to raise
the hair traps a thicker layer of air above the skin
the air insulates the skin against heat loss
Explain what happens to hairs when we are warm?
The hair erector muscle relaxes which causes the hair to lower
a thin insulating layer of air is trapped above the skin
more heat is lost to the environment
What does vasoconstriction mean?
a response to being too cold
the process involves the narrowing of blood vessels at the skin surface to reduce heat loss through the surface of the skin
What does Vasodilation mean?
a response to being too hot
process includes the widening of blood vessels at the skin surface to increase heat loss through the surface of the skin
State two internal conditions that need to be controlled in the human body
temperature
level of glucose in blood
State one factor that can cause blood glucose levels to:
decrease
increase
decrease- after exercise
increase- eaten a meal
Name the two hormones released as part of glucose regulation
insulin
glucagon
Name the two organs involved in glucose regulation and describe its function
pancreas- releases the hormones
liver- responds to the hormones
When blood glucose levels increase
a) which hormone is released?
b) what affect does this have on the liver?
a) insulin
b) liver takes in excess glucose from the blood and stores as glycogen
When blood glucose levels decrease
a) which hormone is released?
b) what affect does this have on the liver?
a) glucagon
b) liver breaks down glycogen and releases glucose into the blood
Explain what happens if there’s an increase in blood glucose levels? (6 mark)
Blood glucose levels can rise after eating carbohydrates/sugar
The PANCREAS produces the hormone INSULIN
The insulin travels in the bloodstream to the LIVER and muscles.
Insulin makes glucose move from the BLOOD into the liver and muscles
Glucose is stored in the liver and muscles as GLYCOGEN
This decreases the blood glucose levels back down to normal
Explain what happens if there’s a decrease in blood glucose levels? (6mark)
Blood glucose levels can fall after exercising
The PANCREAS produces the hormone GLUCAGON and stops producing insulin
The GLUCAGON travels in the bloodstream to the LIVER and muscles.
The liver converts the GLYCOGEN into glucose which is released into the blood
This increases the blood glucose levels back up to normal
