Science revision homeostasis

What is a stimulus?

It is any detectable change in the internal or external environment that pulls a physiological value away from its normal set point.

What is a response?

A response is the final action taken by the body to counteract the stimulus and bring the physiological value back to its normal set point.

What does physiological mean?

It relates to how a living organism and its parts function normally.

What is a set point?

It is the ideal target for your body to try and keep you healthy.

What is a receptor?

It is a specialised cell, tissue or nerve ending that detects changes in the environment.

What is a effector?

It is the organ, tissue or cell that carries out the response to fix the problem.

What is homeostasis?

It is the steady, balanced internal conditions maintained by living things. Also your bodies way of regulating your systems.

What is your peripheral nervous system and what does it do?

It is the system of nerves outside the brain and spinal cord. Its role is to transmit sensory imput to the brain and send information from the brain to the rest of the body.

What is the autonomic system?

It is the part of the peripheral system that regulates involuntary physiological processes necessary for survival.

What is the somatic system?

It is the part of the peripheral system that controls voluntary movements.

What is the central nervous system?

It consists of the brain and spinal cord and is the brains primary control system processing sensory information and directing voluntary and involuntary actions.

What is a neuron?

They are the building blocks of the nervous system and are designed to transmit information around your body.

What are sensory neurons for and give examples?

They carry messages from your senses to your brain and spinal cord. An example is photoreceptors in your eyes.

What are relay neurons for?

They carry information between sensory and motor neurons in the central nervous system.

What are motor neurons for?

They carry instructions from the central nervous system to the muscles or glands so the body can react.

What is a reflex arc?

It is the response pathways starting from a stimulus, receptor, control centre, effector and finally response. This is an involuntary response.

What is a synapse?

It is a specialised junction in which nerve impulses pass from one neuron to another or to an effector cell like a muscle or gland.

What is a neurotransmitter?

It is a chemical messanger that neurons use to transmit signals across a tiny gap called a synapse to another cell.

What is the endocrine system?

It is a network of glands and organs that make and release chemical messengers called hormones directly into the blood stream.

What is a negative feedback loop?

It is a biological mechanism that counteracts a change to restore homeostasis.

Which is more common in the body a negative or positive feedback loop?

A negative feedback loop is much more common.

What is a positive feedback loop?

It is a biological mechanism that amplifies or accelerates a change moving a variable further away from set point.

What is a gland?

It is a cell, group of cells, or an organ that synthesises and secretes chemical substances.

What is the use of a gland?

To produce and secrete specific substances needed to eliminate waste or for a bodily function.

What is an endocrine gland?

It is a ductless organ that releases chemical messengers called hormones directly into your bloodstream.

What is a hormone?

They are chemical messengers produced by specalised glands that travel through the bloodstream.

What is the use of hormones?

They are chemical messengers that target organs and tissues to regulate essential bodily functions.

What are some key functions of hormones?

Things like metabolism, growth and development, stress responses, reproduction and sleep and mood.

What is the importance of maintaining body temperature?

This is important because it stabilises enzymes and proteins, maintains cellular metabolism, and is vital for organ protection as severe changes in temperature can lead to organ failure.

What is the importance of maintaining pH levels?

Lots of things rely on pH levels like protein structure and function, enzyme activity, oxygen delivery, cellular metabolism and ion transport and biochemical intermediates.

What is the importance of maintaining hormone levels?

Lots of things rely on hormone levels like stress and growth response, enzyme activity, fluid and electrolyte activity, cellular energy and metabolism.

What is the importance of maintaining water and fluid levels?

It helps to maintain things like cell volume and shape, electrolyte balance, blood volume and pressure, and waste removal regulation.

What is the stimulus response pathways?

It is a set of things that happen as your body is responding to stimulus and making a decision. The order goes stimulus, receptor, control centre, effectors and lastly response.

What is the stimulus response pathway when a ball is coming at you?

Firstly the stimulus is the ball, then you use your photoreceptors to see whats happening, this sends a message to your central nervous system which then stimulates the effectors which is arm and hand muscles leading you lastly to your response which is catching the ball.

What is the stimulus response when you touch a hot dish?

The stimulus is you touching a hot dish, then your receptor is your thermoreceptors, it sed the message to your CNS which triggers your effector which is arm muscles to respond by moving the hand away.

What are the types of receptors?

Auditory receptors, thermoreceptors, photorecptors, chemorecptors and mechanrecptors.

What are reflex actions?

They are involuntary actions such as a knee jerk or sneezing.

What is the difference between response pathways and reflex arc?

A response pathway goes through the CNS for conscious decision making where a reflex arc simply uses receptors then straight away responds.

What are the different glands in the endocrine system?

The pineal gland, pituitary gland, thyroid gland, adrenal gland, pancreas, ovaries and testes.

What does the adrenal gland do?

It releases adrenaline and cortisol for a fight or flight response.

What are functions of the nervous system?

Sensory input, integration and motor output.

What things in your body should constantly stay the same?

Your core body termperature, pH levels, blood glucose,

What things in homeostasis require a negative feedback loop?

Temperature regulation, blood glucose levels, blood pressure, water balance, blood ph, and calcium levels.

What things in homeostasis require a positive feedback loop?

childbirth, blood clotting, and breastfeeding.

What are the similarities of the nervous and endocrine systems?

They both help maintain homeostasis and control body functions. They also both send messages around the body to respond to changes.

What are the differences of the nervous and endocrine systems?

The nervous system send electrical impulses through the body for fast and short lasting changes while the endocrine system releases hormones causing slower but longer lasting responses.

How does the nervous system coordinate the bodies response to stimuli?

When the body feels stimuli then nerves from the nervous system carry this to the brain and the brain will send a electrical impulse through the nerves to the effectors.

How does the endocrine system coordinate the bodies response to stimuli?

The endocrine system will detect a change and it will release hormones into the bloodstream which will control things like growth, metabolism and blood glucose.

What are the glands in the endocrine system?

The Hypothalamus, Pituitary gland, Thyroid gland, Parathyroid gland, Adrenal gland, Pineal gland and pancreas (Ovaries in women and Testes in men)

What does the Hypothalamus do?

Links the nervous system to the endocrine system and controls the pituitary gland.

What does the Pituitary gland do?

Often called the "master gland" because it releases hormones that control many other endocrine glands.

What does the Thyroid gland do?

Controls your metabolism (how your body uses energy).

what does the Parathyroid gland do?

Four tiny glands that regulate calcium levels in your blood and bones.

What does the adrenal glands do?

Produce hormones like cortisol and adrenaline that help handle stress, blood pressure, and metabolism.

What does the Pineal gland do?

Releases melatonin, which helps regulate your sleep-wake cycles.

What does the pancreas do?

Produces insulin and glucagon to control blood sugar levels.

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