Yr 11 Bio Human Responces

Nervous system

The body system that coordinates and regulates body functions using electrical impulses

Central nervous system (CNS)

The brain and spinal cord

Peripheral nervous system (PNS)

All the nerves outside the brain and spinal cord

Coordination

Organising different parts of the body so they work together

Regulation

Controlling body processes so the body functions properly

Neuron

A specialised cell that carries electrical impulses around the body

Electrical impulse

An electrical signal that travels along a neuron

Sensory neuron

Carries impulses from a receptor to the CNS

Relay neuron

Carries impulses within the CNS from a sensory neuron to a motor neuron

Motor neuron

Carries impulses from the CNS to an effector

Receptor

A specialised cell that detects a stimulus and starts a nerve impulse

Stimulus

A change in the environment that is detected by a receptor

Effector

A muscle or gland that produces a response

Five senses

Sight hearing smell taste and touch

Sense receptors

Specialised cells that detect specific types of stimuli

Reflex action

A rapid and automatic response to a stimulus

Reflex arc

The pathway of a reflex: receptor → sensory neuron → relay neuron → motor neuron → effector

Synapse

The junction between two neurons

Neurotransmitter

A chemical messenger that carries a signal across a synapse

Presynaptic neuron

The neuron before the synapse that releases neurotransmitters

Postsynaptic neuron

The neuron after the synapse that receives neurotransmitters

Synaptic gap

The small gap between two neurons

Vesicles

Small structures in the presynaptic neuron that store neurotransmitters

Receptor proteins

Proteins on the postsynaptic neuron that bind to neurotransmitters

Diffusion

The movement of particles from an area of high concentration to low concentration

Synapse transmission

An electrical impulse causes neurotransmitters to be released from vesicles into the synaptic gap

Neurotransmitter reabsorption

Neurotransmitters are reabsorbed into the presynaptic neuron or diffuse into the fluid around the neuron

One-way transmission

Synapses ensure that nerve impulses travel in one direction only

Endocrine system

A system of glands that produces hormones to control body functions

Endocrine gland

A gland that releases hormones into the bloodstream

Hormone

A chemical substance produced by a gland and carried by the blood that affects specific target organs

Target organ

An organ or tissue that responds to a specific hormone

Nervous control

Control of body functions using electrical impulses

Hormonal control

Control of body functions using hormones carried in the blood

Nervous vs hormonal control

Nervous control is faster and usually has a shorter-lasting effect

Adrenaline

A hormone released by the adrenal glands during fight or flight situations

Fight or flight

The body's response to danger that prepares it for rapid action

Metabolic activity

The chemical reactions that occur inside cells

Adrenaline effects

Adrenaline increases breathing rate

Adrenaline and blood glucose

Adrenaline increases blood glucose concentration to provide more energy for respiration

Adrenaline and heart rate

Adrenaline increases heart rate to deliver more oxygen and glucose to muscles

Adrenaline and breathing rate

Adrenaline increases breathing rate to provide more oxygen for respiration

Adrenaline and pupils

Adrenaline increases pupil diameter to allow more light into the eyes