B10 - The Human Nervous System Flashcards
Define homeostasis (1 mark)
The regulation of conditions in our body maintaining a stable internal environment, for example: internal body temperature
Why is homeostasis important? (2 marks)
It is important for maintaining optimal condition for enzyme action and all cell functions
Give examples of homeostasis in the human body. (3 marks)
- When you exercise your muscles get hotter (more strained, more lactic acid production)
- when you have eaten a meal and your blood sugar levels go up (glucose levels increased)
- in hot weather you lose water through sweating (perspiration)
Describe homeostasis (3 marks)
The regulation of the internal conditions of a cell or organism to maintain optimum conditions for functions, in response to internal and external changes. For instance; when internal body temperature is normal or slightly elevated, the enzymes are optimised and functions in the body are increased in speed.
Why is it important to respond to changes in the internal or external environment? (2 marks)
It is important to respond to these environmental changes as it helps maintain the body’s optimum conditions for the cellular enzymes and its activities.
What internal conditions can be controlled? (3 marks)
- body temperature
- the water content of the body
- blood glucose concentration
What does the automatic control system involve? (2 marks)
They involve either NERVOUS or CHEMICAL responses
What are receptors (1 marks)
Cells that detect stimuli - changes in the internal or external environment. They then send electrical impulses to the neurons to react to.
Describe a receptor (3 marks)
Cells that detect changes in the external or internal environment. These changes are known as stimuli. Receptors may be part of the nervous or the hormonal control systems of the body and is responsible for the emitting of electrical impulses to the neurons or CNS (brain, spinal cord, etc.)
What are coordination centres - CNS (1 mark)
Areas that recieve and process information from receptors (e.g. brain - CNS)
Describe coordination centres - CNS (3 marks)
They are areas that recieve and process the information from the receptors. They send out signals (electrical impulses) and coordinate a response from the body (via. neurons). They include the brain (CNS) that acts as a coordinate centre for both the nervous system and parts of the hormonal system, the spinal cord (CNS), pancreas and some other organs.
What are effectors? (1 mark)
Areas (usually muscles or glands) that bring about responses in the body
Describe effectors (3 marks)
Muscles or glands that bring about responses (via. neurons) to the stimulus that have been recieved (via. receptors). These responses restore conditions in the body to the optimum levels.
Define stimuli/us
Changes in the external or internal environment that can be detected by receptors.
Name the different types of sense receptors (5 marks)
- ears
- eyes
- skin
- nose
- tongue
Give one example of what the different types of sense receptors respond to (5 marks)
- Ears receptors are sensitive to changes in position for balance and sensitive to sound.
- Eyes receptors are sensitive to light and darkness
- Skin receptors are sensitive to touch, pressure, pain and temperature changes.
- Nose and tongue receptors respond to chemicals for smell and taste.
Define a nerve (1 mark)
Bundle of hundreds or even thousands of neurons/ones
Define a neurone (1 mark)
Basic cells of the nervous system that carry electrical impulses around the body
What are the types of neurones (3 marks)
- sensory neurons
- motor neurons
- relay neurons
Describe a nerve and each neurone (5 marks)
Nerves carry electrical impulses around the body that passes along special cells called neurones. There are two main types of neurons: SENSORY neurons - which are the cells that carry impulses from your sense organs to your CNS, and the other type are MOTOR neurons - they carry information from your CNS to the rest of your body by electrical impulses to make the right bits of your body.
What may an effector be (2 marks)
Effectors may be muscles or glands
Describe two examples of effectors (4 marks)
- Muscles, as your muscles respond to the arrival of impulses by contracting.
- Glands, your glands respond by releasing (secreting) chemical substances.
Define the nervous system (1 mark)
The nervous system consists of the CNS - the brain and the spinal cord.
Explain the nervous system (2 marks)
Carries electrical impulses so you can react quickly to changes in your surroundings
Why do you need a nervous system (2 marks)
The nervous system uses electrical signals to communicate with different parts of the body, without this your body internally and externally will not be able to react to changes in your surrounding, placing you at a fatal risk of danger.
What is the order to which the nervous system works (4 marks)
Stimulus (light) —> Receptor (eyes) —> Coordinator (CNS) —> Effector (for eg. muscle) –> Response.
Explain what happens to your nervous system from stimuli to effector (5 marks)
The receptor sends an electrical impulse along a SENSORY neuron, carrying information about a change in the environment to the coordinator (CNS). Once all the incoming information has been processed, the coordinator send impulses down, via. MOTOR neurones. These MOTOR impulses stimulate the effectors to bring about responses needed in any particular situation.
Explain what happens to your nervous system, when you see a piece of fruit, pick it up and eat it. (6 marks)
Light from the piece of fruit is detected by the sensory receptors in the eyes (via. Refraction), then an electrical impulse travels along the SENSORY neuron to the brain (CNS) - where information is processed in the brain and another electrical impulse is sent along a MOTOR neuron to the muscles of the arm and hand (the EFFECTOR) so you can pick up the piece of fruit and then put it in your mouth. The taste receptors sensitive to chemicals for smell and taste on your tongue send information to the brain (CNS) about taste.
Give two methods of how quickly nerve impulses travel in your body (4 marks)
- Use a ruler drop test or digital sensors to measure how quickly you react to visual stimulus.
- Stand in a circle holding hands with your eyes closed and measure how long it takes a hand-squeeze to pass around the circle.
What are reflexes? (1 marks)
Ralid and automatic responses of the nervous system that do not involve conscious parts of the brain (CNS).
Name a couple examples of human reflexes (2 marks)
They control everyday bodily functions, such as: breathing and digestion, and help to avoid dangerous situations.
Wh are reflexes important? (2 marks)
They help you to avoid danger or harm because they happen so fast
Why is it important that reflexes dont go to the conscious areas of your brain? (1 mark)
Which makes it quicker to react and therefore reduces damage to the body
Define a sensory neuron
A sensory neuron is a neuron that carries electrical impulses from the sensory organs to the central nervous system (CNS)
Define a motor neurone (1 mark)
Motor neurones carry impulses from the central nervous system (CNS) to the effector organs
Define a relay neurone (1 mark)
Relay neurons connect a sensory neurone and a motor neurone, and are found in the CNS