1.6 Nervous system and hormones Flashcards
What is a voluntary response
Under concious control - brain involved
What is a reflex action
Automatic
does not involve the brain/concious control
What is the order of a reflex arc
Stimulus - Receptor - Sensory Neurone - Association Neurone- Motor Neurone - Effector Muscle - Response
Where are the association neurones found
In the Central nervous system
What are some of the features of a neurone
Long to carry impulse quickly
Have insulating sheath - to increase speed of transmission of impulse
Branched nerve endings - so messages can get to other parts of body rapidly
Where in the spinal cord do the 3 neurones meet
The grey matter
What is the gap called between neurones
Synapse
What happens in the synapse
When the electrical impulse arrives at the end of the neurone a chemical (neurotransmitter) is released
this passes or diffuses across the synapse
If enough passes across the synapse to the next neurone it will start an impuse in the next neurone
What is a hormone
A chemical
Made in a gland
Released into the blood stream
travels to target ORGAN
What is the name of the hormone that regulates blood glucose levels
Insulin
Where is insulin made
Pancreas
When is more insulin released
When person has eaten a meal
What is the target organ of insulin
Liver
What effect does insulin have on muscle cells and liver
Liver and muscle cells absorb more glucose
More respiration occurs
Liver cells also store glucose as GLYCOGEN
If blood glucose levels drop what happens to insulin
Pancreas detects low levels of glucose
Less insulin is released
What is the condition caused by pancreas not functioning properly
Diabetes
How is Diabetes 1 different to Diabetes 2
Diabetes 1 is caused by pancreas producing NO insulin
Occurs early in life
Rely on injections of insulin
Diabetes 2 caused by pancreas producing LESS insulin
Is caused by lifestyle - happens later in life and linked to obesity
Can be controlled by diet but later may need injections
What are symptoms of diabetes
Excessive thirst
Glucose in urine
High blood glucose levels
Lethargic
What are long term effects of diabetes
Eye damage,
kidney damage
stroke
heart disease
What is meant by the term homeostasis
Maintaining a constant internal environment e.g. blood glucose levels, water and ion levels in blood
What are the 2 main jobs of the kidneys
To excrete excess ions and waste urea (from excess proteins)
To regulate water levels of body
Describe the process of urine formation in kidneys
Blood high in ions, urea and water enter kidneys by renal artery
Contents are filtered in the cortex of kidney
Any materials required by body eg all glucose, water and ions are reabsorbed back into blood in medulla
Any unwanted ions, excess water and urea are excreted as urine via the renal pelvis
pass down ureter and stored in bladder before leaving via urethra
What is ADH
A hormone released from pituitary gland
what part of the body monitors water levels in blood
Hypothalamus in brain
How does ADH control water levels
If you have exercised/sweated alot - water levels in blood are low
Hypothalamus detects low water levels
Pituitary gland releases MORE ADH
Causes kidneys to reabsorb more water back into blood
Lower volume of a concentrated urine produced
What is the name of the growth response in plants to light
Phototropism
What is the name of the hormone involved in phototropism
Auxin
Where are auxins made
In the plant shoot tip or root tip
Describe the effect auxins have on plant growth
Cause more cell elongation
Describe the effect auxins have if light is hitting a plant at an angle
More auxin will diffuse from the shoot tip down the shaded side of plant
this causes more cell elongation on the shaded side
The shoot will bend to wards the light
What is the benefit to the plant in phototropism
It will get MORE Light so can photosynthesis MORE
