Unit 12: Human Regulation and Reproduction Assignment 2: The Nervous and Endocrine Systems
Starter Activity Complete the anagrams… Write a definition of each word!
Lesson Objectives To understand the basic structure of sensory, relay and motor neurons. To be able to describe the function of each part of a neuron. To revise the function of a synapse.
Draw a Nerve Cell On your mini whiteboards, draw a labelled diagram of a nerve cell. (Nerve cell = Neuron / Neurone)
Did it look like this?
Neurons Specially adapted cells (can you remember how they are adapted?) Carry electrochemically charged impulses (this needs energy from ATP so there are lots of mitochondria to carry out respiration) Use Neurotransmitters (cells feature a large amount of endoplasmic reticulum to make these proteins)
Sensory Receptors Respond to an environmental stimulus with an electrical change. The resulting signal is conducted to a sensory neuron.
Sensory Receptors: Sense Sense Organ Sensory Receptor Cells Sensitive to… Sight Eye Rod and Cone cells in the retina Changes in light Smell Hearing Taste Touch
Sensory Receptors: Sense Sense Organ Sensory Receptor Cells Sensitive to… Sight Eye Rod and Cone cells in the retina Changes in light Smell Nose Olfactory Cells Chemicals in the air Hearing Ear Hair cell receptors (inner ear) Vibrations in the air particles Taste Tongue Chemoreceptors on the taste buds Chemicals in food and drink. Touch Skin Pressure /Thermo receptors Changes in temperature and pressure
Stimulus Receptor Sensory Neuron Inter neuron Motor neuron Effector Response
Types of Neuron Sensory Relay Motor
Sensory Neurons
Sensory Neurons These cells transmit an electrical impulse from a sensory receptor to a relay neuron (interneuron). Long cells Cell body is located away from the dendrites. Why?
Relay Neurons (interneurons)
Relay Neurons Transmit a nerve impulse from a sensory neuron to a motor neuron in the reflex arc. Found in the central nervous system (spinal cord / brain)
Motor Neurons
Motor Neurons Transmit electrical impulses from sensory/relay neurons. Cause a change in an effector (e.g. muscle movement)
https://www.youtube.com/watch?v=cUGuWh2UeMk
Neuron Structure Complete the handout using your notes and the biology text books.
Synapses Draw a synapse on your mini whiteboard
Did it look like this?
Neuromuscular Junctions
What do synapses do? A Synapse is where two nerve cells meet There is a tiny gap between the pre synaptic membrane (synaptic knob) and the post synaptic membrane. An electrical impulse is converted into a chemical messenger (neurotransmitter) to pass over the synaptic gap, this is then converted into an electrical signal again.
Neurotransmitters Acetylcholine Noradrenaline Serotonin Dopamine GABA
Acetylcholine (ACH) 1st Neurotransmitter to be discovered Also present in the CNS and PNS (Neuromuscular junctions) Most common NT Vital in the transmission of nerve impulses
Noradrenaline Mostly involved in stimulating heart rate Sympathetic Nervous System Involved in the ‘’fight or flight’’ response.
Serotonin Found in the brain synapses Responsible for mood balance Involved in mood, emotion, sleep and appetite. High levels make us feel really good Low levels linked to depression Chocolate can increase the production of serotonin. (Tryptophan) Drugs like ecstasy increase serotonin.
Dopamine Focus, movement, co-ordination, memory. Parkinson's = loss of dopamine Reward system in pleasurable behaviour) (when eating, having sex or carrying out addictive behaviour) Disruption to the dopamine system is linked to psychosis (schizophrenia)
Complete the handout ‘Synapses’ Class / Home Work Complete the handout ‘Synapses’
Lesson Objectives To understand the basic structure of sensory, relay and motor neurons. To be able to describe the function of each part of a neuron. To revise the function of a synapse.