B5

Homeostasis

A stable internal environment of different species in a community in order to maintain the optimum conditions for enzyme activity and cellular function

Examples of conditions maintained by homeostasis

Body temperature

Water levels

Blood glucose concentration

Community

A group of of interacting organisms that share a common habitat

Adrenal gland

Located in the kidneys

Produces Adrenalin

Prepares body for fight or flight response

Targets the heart and lungs

Examples of effects from adrenaline

dilated pupils

Increase of heartbeat and breathing

Increased blood glucose

Increase of oxygen supply

What is the function of the nervous system

allows the body to react to its surroundings and coordinate an appropriate response.

How does a stimulus lead to a response being carried out by the body?

Stimulus is converted into an electrical response by the receptors

The electrical impulse passes along the sensory neurones to the central nervous system (CNS).

The CNS coordinates inappropriate response and an electrical impulse is sent along the the motors to the effect which carries out the response.

What happens at the synapse between a sensory and a relay neurone

A chemical diffusers across the gap and stimulates a new impulse which passes along the relay neurone

What is the difference between a reflex pathway and a conscious pathway?

Within a reflex pathway? The coordination centre is a really neurone found in this spinal cord/the unconscious part of the brain. And a conscious pathway the coordination centres in the consciousness part of the brain.

Reaction time practical

Sit with non dominant arm resting on the edge of a table

Person B holds the ruler between thumb and fore finger ,drops the ruler. The zero end of the ruler is level with their thumb and finger .they should be standing

Person A will try catch the ruler as fast as they can

Reaction time is measured by the number of Ron the ruler where it has been caught . The number should be read from the top of the thumb the further down the ruler is caught the slower the reaction time .

Repeat the steps and then calculate a mean for the results

Endocrine system compared to Nervous system

nervous system reacts faster

Endocrine system -hormones have a longer lasting effect

What is a hormone?

A hormone is a chemical messenger secreted by a gland. It travels in the blood to target an organ which causes a response.

What type of organ secretes Homeones

Glands

Give the name of the bodies coordination system which involves hormones

The endocrine system

Controlling blood sugar glucose level -high levels

Insulin is secreted by the pancreas if blood glucose levels are too high.

Insulin binds to the receptors on the liver and muscles causing excess glucose to be converted to glycogen and then stored.

Insulin causes glucose to enter the liver. Glucose turns into glycogen by the liver .blood glucose will decrease .

Controlling blood sugar glucose level -when low

The pancreas secretes the hormone Glycogen

glycogen binds to the liver cells causing glycogen to be converted into glucose and released into the blood .

Blood glucose increased

How is blood glucose concentration controlled using a negative feedback loop?

When the blood glucose concentration rises are false below the optimum a hormone secreted by the pancreas.

The action of either hormone insulin or glucagon helps bring back the concentration to the correct level

What is type one diabetes? How can it be treated?

Treated by insulin injections,limit carbohydrate intake,pancreas and pancreatic call transplant.

It is an autoimmune disorder

The pancreas does not produce sufficient insulin to control the blood glucose concentration.

As a result, blood glucose levels are often very high leading to excessive urination tightness and weight loss.

What is type two diabetes? How can it be treated?

regular exercise losing weight a carefully controlled low carbohydrate diet yeast of drug which increase insulin production

A disorder when the body cells stop responding to insulin leading to an uncontrolled blood glucose concentration.

Risk factors are obesity.

What is osmosis?

The movement of water particles from a high concentration to a low concentration through a partially permeable membrane without energy.

What does the negative feedback mean?

Refers to the mechanisms by which homeostatic maintains conditions within an optimal range and move away from the optimum results in the mechanisms which you returned back to the optimum

Define basal metabolic rate

The base of metabolic rate is the speed at which chemical reactions secure in the body when it is at rest

puberty changes in the body

Breast develop pubic hair

Men grow taller and voice deepens

Menstruation

Caused by the drop in progesterone, it maintains the lining but the drop of it means the uterus linings breaks down

FSH and LH

what is an embryo

Embryos are tiny balls of cells which develop from metic division of a fertilised egg.

Thyroid gland

Produces thyroxine which is involved in regulating the rate of of metabolism,heart rate and temperature

Pituitary gland

May be called the master gland because other hormones act on other glands

Secretes several hormones in the body

Is secretes the human growth hormone stimulates a thyroid gland

stimulates ovulation and the production of Oestrogen in the ovaries and the production of sperm in the testes.

What is the role of the pancreas in the endocrine system?

Secretes insulin to control blood glucose levels