BY4: The Nervous System
For the nervous system to carry out its function effectively it is dependent upon a continuous input of information from inside the body and from the environment. This input is detected by sensory receptors and relayed to effectors. That is, responses to all stimuli involve the reception of information and its transfer from the receptor to an effector via the nervous system.
The mammalian nervous system is dual in nature. The central nervous system (CNS) co-ordinates and controls the activities of the animal. The peripheral nervous system (the nerves and ganglia) forms the connecting link between the organs and the central nervous system. Many body functions and actions are controlled by reflex actions which involve both parts of the nervous system.
The nervous system
The nervous system:
Receptors which range from specialised sensory cells (such as those in the skin) to the more complex sense organs such as the ear and eye, detect the information from inside the body and from the surroundings. It is the role of the central nervous system (CNS), which is made up of the brain and spinal cord, to process the information and initiate a response.
Effectors bring about responses. Effectors may be muscles or glands.
Sensory receptors detect one form of energy and convert it into electrical energy. They are acting as transducers. The electrical impulses travel along nerves and are called nerve impulses. Some nerves bring information to the CNS and others take the information away.
There are a number of different types of receptors including:
For the nervous system to carry out its function effectively it is dependent upon a continuous input of information from inside the body and from the environment. This input is detected by sensory receptors and relayed to effectors. That is, responses to all stimuli involve the reception of information and its transfer from the receptor to an effector via the nervous system.
The mammalian nervous system is dual in nature. The central nervous system (CNS) co-ordinates and controls the activities of the animal. The peripheral nervous system (the nerves and ganglia) forms the connecting link between the organs and the central nervous system. Many body functions and actions are controlled by reflex actions which involve both parts of the nervous system.
The nervous system
The nervous system:
- Detects changes or stimuli inside the body and from the surroundings
- Processes that information
- Initiates an appropriate response
Receptors which range from specialised sensory cells (such as those in the skin) to the more complex sense organs such as the ear and eye, detect the information from inside the body and from the surroundings. It is the role of the central nervous system (CNS), which is made up of the brain and spinal cord, to process the information and initiate a response.
Effectors bring about responses. Effectors may be muscles or glands.
Sensory receptors detect one form of energy and convert it into electrical energy. They are acting as transducers. The electrical impulses travel along nerves and are called nerve impulses. Some nerves bring information to the CNS and others take the information away.
There are a number of different types of receptors including:
- Thermoreceptors = which detect changes in temperature
- Photoreceptors = which detect changes in light
- Chemoreceptors = which detect changes in the presence/absence of specific chemicals
The Spinal Cord
This is the part of the central nervous system that passes through and is protected by the vertebral column and from which most of the peripheral nerves originate. It consists of a central area of grey matter, consisting mainly of nerve cell bodies, and a surrounding area of white matter which consists of nerve fibres.
Sensory fibres of the peripheral system enter the cord via the dorsal routes. The cell bodies of the sensory fibres are found in the dorsal root ganglia which lie alongside the spinal cord. The motor fibres leave via the ventral routes.
The functions of the spinal cord are to relay impulses in and out of any particular point along the cord and to relay impulses up and down the body, including to and from the brain.
This is the part of the central nervous system that passes through and is protected by the vertebral column and from which most of the peripheral nerves originate. It consists of a central area of grey matter, consisting mainly of nerve cell bodies, and a surrounding area of white matter which consists of nerve fibres.
Sensory fibres of the peripheral system enter the cord via the dorsal routes. The cell bodies of the sensory fibres are found in the dorsal root ganglia which lie alongside the spinal cord. The motor fibres leave via the ventral routes.
The functions of the spinal cord are to relay impulses in and out of any particular point along the cord and to relay impulses up and down the body, including to and from the brain.