Topic: Nerves and neurons

Author: Elżbieta Szedzianis

Target group

7th‑grade students of an eight‑year elementary school.

Core curriculum

III. Human body

9. Nervous system. Student:

1) recognizes the elements of the central and peripheral nervous system (on a model, drawing, according to the description, etc.) and describes their functions.

Lesson aim

Students describe the build and functions of the nervous system and the build and functions of neurons.

Key Success Criteria

• you will talk about the elements of the central and peripheral nervous system, as well as motor and sensory nerves;

• you will describe the construction of a neuron in connection with its function;

• you will present the construction of a neuron using a model.

Key competences

• communicating in the mother tongue;

• communicating in a foreign language;

• Mathematical competence and basic competences in science and technology; 

• digital competence;

• learning to learn;

• Social and civic competences.

Methods/forms of work

Brainstorming, work with text, workshop method.

Individual or group work.

Teaching measures

• abstract;

• interactive whiteboard or traditional blackboard;

• tablets/computers;

• old newspapers or brown paper;

• markers;

• a ball.

Lesson plan overview (Process)

Introduction

1. Teacher writes down the following question on the interactive whiteboard:

• What do we know so far about the nervous system?

• What is it that we want to learn?

• What have we learned today?

He encourages students to answer the first question. All the answers of the students are written down on the whiteboard (brainstorming). When the students run out of ideas, the teachers check if the basic information on the functions of the nervous system was mentioned, i.e. receiving information from the environment and reacting to it. If they are missing, he writes them on the whiteboard. Next, the teachers asks volunteers to write down on the whiteboard the answers to question number 2. He reads them out loud and explains which problems the students will learn about during the class, which they will learn during the following classes and finally, which they will learn about in high school.

2. The teacher gives the topic and the aim of the lesson and explains the criteria of success.

Realization

1. The teacher asks the students to read the part titled „Neural cells and nerves”,
   and while reading, the students should pay attention to the shape of the neurons and the connection between how these cells are built and
   what functions they have. The students should also focus on synaptic conduction. He asks the students to memorize as much information as they can, because soon they will become the models of neurons and they will have to reflect their task.

2. The teacher hands out newspaper sheets or sheets of brown paper. The teacher asks the children to use them to prepare hats and write the name ‘neuron’ on them. He does the same thing, and then, everybody puts on their hats. On the forearm of the right hand, the teacher writes down the word ‘dendrite’, whereas on the forearm of the left hand - the word ‘axon’. On both hands he writes the word ‘synapse’.
   He shows the writings to the students and encourages them to write the same words on their forearms and hands. Then, the teacher asks the children to line up one next to the other in order for the ‘axons’ to be close to the ‘dendrites’. Then, he takes a ball into his right hand (the ‘dendrite’) and he passes it to his left hand (‘axon’), and passes it to a student standing nearby, so that the student takes the ball into his right hand (‘dendrite’), and repeats the movements of the teacher. Other students do exactly the same. They are trying to pass the ball as quick as they can. After finishing this exercise, the students talk about the build and the functions of the neurons, referring to the model they have created.

3. Students complete interactive exercises.

4. Students look at the illustration that shows the central nervous system and the peripheral nervous system.The teacher reminds the students that the basic functions of the nervous system are to receive information from the environment and to react to such information. He then asks the students to explain this claim by analysing the scheme.

5. On their own, the students draw the structure of the nervous system in their notebooks: they draw the division into the central nervous system (brain and the spinal cord)
   and the peripheral nervous system (sensory and motor nerves).

Summary

Students answer the third question, written down on the board at the beginning of the lesson.

Optional homework

Create a model of a neuron from various materials.

The following terms and recordings will be used during this lesson

Terms

Texts and recordings

Nervous system

The nervous system is composed of several subsystems that work together with each other and with the rest of the body. Due to its build, we distinguish the central nervous system (CNS) and the peripheral nervous system (PNS). The central nervous system consists of the brain and spinal cord. CNS is the control centre for the entire body. It receives, analyzes and processes information that comes from the environment and from inside the body and sends the answers to the executive organs. It is possible thanks to cranial nerves and spinal nerves, which connect the brain and the spinal cord with the rest of the body. It’s them, together with neural plexuses and ganglia, that create the peripheral nervous system. The system receives information and sends it to the central nervous system and conducts the answers from the brain and the spinal cord to the executive organs.

The peripheral nervous system can be divided into the somatic nervous system and the autonomic nervous system. They cooperate in order to maintain the balance inside the body. The somatic nervous system receives stimuli from the surroundings and directs the skeletal muscles. The autonomic (vegetative) nervous system receives stimuli that come from inside the body and controls the work of organs, whose actions are independent from our will (e.g. the heart muscle).

In autonomic nervous system we distinguish a sympathetic and a parasympathetic part. Both, using various nerves, influence the same organ, but they have opposite actions. The sympathetic system boosts the activity of many organs (and slows down the activity of others), and mobilizes the body to act in stressful situations. The parasympathetic system has the reverse function - it slows down the activity and calms the body. The sympathetic system causes, for example, the dilation of pupils (mydriasis) that happens when the body is prepared to fight or flight. In order for this to be successful, the body must register all possible threatening movements and details of the surroundings. When the danger passes, the parasympathetic system causes the narrowing of the pupils (miosis), causing the eyes to be less sensitive to information from the surroundings.

The basic structural and functional units of the nervous system are the neural cells – neurons. Their tree‑like shape is the manifestation of how well they adapted to receiving and transferring information. The body of neural cell has multiple protrusions projecting into many ways. There are the so‑called dendrites. They are short and very arborescent and they conduct information towards the perikaryon. They constitute about 80% of the total mass of the neuron. A single long protrusion (in humans it can measure up to 100 cm) is called an axon. It is responsible for transferring information from the perikaryon to other neurons or executive organ. It is also called a nerve fibre.

The cell membrane of the neuron has an ability to conduct information in form of nerve (electrical) impulses. The impulses are delivered by dendrites to the membrane covering the body of the nerve cell, and from there they run along the axon’s cell membrane to other neurons, muscles and, glands. The protrusions of the neurons do not touch each other directly. They are divided by a ridge, the so‑called synaptic cleft, through which the impulses are delivered from the axon of one cell to the dendrite of the other (or from the axon to, e.g. a muscle cell or a gland). The connection of the axon, the cell transferring its impulse, with the cellular membrane of another neuron that receives the impulse or another cell that receives the impulse is called synapse.

In the synaptic cleft, the information is transferred using chemical substances called mediators or neurotransmitters. They are secreted by the corn‑like looking ends of the axons, and in the membrane of the neighbouring dendrites there are receptors, that fit the neurotransmitters spatially. When the electric impulse reaches the corn‑like ending of an axon, the transmitters are released into the cleft. They combine with the receptors that are present in the receiving cellular membrane, which causes the electric impulse to appear and move further towards its axon.

Some axons are covered by a fatty substance called myelin. The myelin insulation around nerves isolates neighbouring neurons and speeds up the conduction of impulses along the nerve fiber. Axons or dendrites of various neurons bundled together and covered from the outside by the connective tissue create nerves. Nerves are responsible for transferring information between the brain or spinal cord and the cells of the body.

• The basic structural and functional units of the nervous system are neurons. In the nervous system, the information is conducted in the form of electric impulses and chemical substances.

• The central nervous system (CNS) consists of the brain and the spinal cord.

• The peripheral nervous system consists of nerves that run from the brain and the spinal cord.

• The autonomic (vegetative) nervous system sustains bodily functions: it receives stimuli that come from inside the body and controls the work of organs, whose actions are independent from our will, allows activity and exertion of the body or slows down the activity of the internal organs.