6.2 Control systems Flashcards
What is the nervous system and what are its two main parts (CNS and PNS)?
The nervous system is a communication network that controls all other systems of your body. Nervous system has two main parts:
* Central nervous system (CNS) – made up of your brain and your spinal cord. The CNS receives information from all over the body, processes that information and then sends out messages telling the body how to respond.
* Peripheral nervous system (PNS) – made up of the nerves that carry messages to and from the CNS and other parts of your body.
What are neurons, and what do its four main parts do (Cell body, dendrites, axon, axon terminal)?
Neurons – carry electrical messages called nerve impulses from one part of your body to another at very high speed. Neuron has four main parts:
* Cell body – contains nucleus which is the control center of the cell
* Dendrites – branch out from cell body and receive messages from other nerve cells, which are then sent on to the cell body.
* Axon – or nerve fiber, sends nerve impulses in only one direction
* Axon terminals – pass the message on to the next neuron
What are the two common types of neurons?
- Motor neurons – these carry messages from the CNS to effectors. Effectors are muscles or glands (tissues that secrete hormones) that put messages into effect
- Sensory neurons – these carry messages from cells in the sense organs (such as eyes, ears, tongue, and skin) to the brain and spinal cord
How does your body control which neurons fire at a certain time?
What is the space between neurons called and what is a neurotransmitter?
Your body needs to control which nerves fire at a certain time. When the nerve impulse reaches the axon terminals a chemical called a neurotransmitter is released into space between the neurons. This space is called synapse. The neurotransmitter carries messages from the axon of one neuron to the dendrite of the next neuron. The dendrite receives chemical messages and sends an electrical signal.
What is Myelin sheath?
Myelin Sheath – In your body the neurons are bundled together to form nerves. Neurons are covered with an insulating layer called a myelin sheath. Electrically insulates the neurons from each other and increases the speed if the nerve impulse.
What is the endocrine system, what are hormones and what are endocrine glands?
Endocrine system – is a communication system that controls the internal environment of the body.
Hormones – are chemical substances that act as messages in the body.
Endocrine glands – produce hormones and release them directly into the bloodstream.
What does the pituitary gland do?
Pituitary gland – coordinates the endocrine system, and responds to information from the hypothalamus. The pituitary gland is often called the master gland because it controls the activities of other endocrine glands such as the ovaries, the testes and the thyroid gland.
What does the hypothalamus gland do?
Hypothalamus – is a portion of the brain, it constantly checks the internal environment, that is the conditions within the tissues, organs, and systems of your body. If these conditions change the hypothalamus responds. The most important function of the hypothalamus is to link the nervous system and the endocrine system. It tells the pituitary gland what to do.
What are target cells?
Target cells – hormones do not affect all cells, only particular cells, the cells it affects are called target cells.
What is homeostasis?
Homeostasis – your body works most efficiently when the internal environment is reasonably constant. The process of maintaining a relatively constant internal environment is known as homeostasis. Homeostasis involves receptors that are sensitive to a particular stimulus and effectors that have an effect on the same stimulus. This type of control is known as feedback system.
