Body Systems Flashcards
Definition of neurons
The main type of cell in the nervous system that carry out messages through electrical impulses.
Definition of nerve impulses
The electrical signal that a neuron transmits.
Definition of cell body
The main part of the nerve cell that contains all necessary components to keep the nerve cell alive like the nucleus (where DNA is stored). The cell body is also known as soma.
Definition of dendrites
A branched extension of the cell body that receive messages from other nerve cells.
Definition of axon
Part of the nerve cell that sends nerve impulses away from the cell body.
Definition of neurotransmitter
Chemicals that allow neurons to communicate with each other throughout the body.
Definition of synapse
The gap between two neurons which neurotransmitters carry a chemical signal across.
Definition of myelin sheath
The insulating layer covering the axon which increases the speed of an electric pulse.
Definition of sensory neurons
Nerve cells that detect changes in the environment via receptors and send messages to the brain.
Definition of motor neurons
Nerve cells that send messages from the brain to muscles or glands that carry out a response.
Definition of interneurons
Nerve cells that connect sensory neurons to motor neurons.
Job of the nervous system
Sense and respond to changes in your environment. This is done by receiving, processing and responding to the stimuli. It is involved in controlling all body movements and other vital systems including the heartbeat, breathing and digesting.
Job of the endocrine system
Regulate body functions by releasing hormones into the bloodstream via glands. The hormones effect growth and development, metabolism and reproduction.
Differences of the nervous system and endocrine system
The nervous system:
1. composed of neurons
2. uses electrical signals and neurotransmitters
3. very fast acting
4. short term effects
5. transmit signals via nerve cells
The endocrine system:
1. composed of glands
2. uses hormones
3. slow acting
4. long term effects
5. transmits signals via the bloodstream
Two parts of the nervous system and what they are made of
The central nervous system (CNS) is the brain and spinal cord. The peripheral nervous system (PNS) connects everything to the brain and spinal cord by nervous tissue.
Function of the peripheral nervous system
Contains all the nervous tissue that links the CNS to the rest of the body. Responsible for sending information from the body to the brain and carrying out commands from the brain to the body.
What does the nervous system consist of
The nervous system is made up of the brain, spinal cord and nerves.
What are the 3 types of neurons
Sensory neurons, motor neurons and interneurons
What are sensory neurons
Nerve cells that detect changes in the environment via receptors and sends messages to the brain
What are motor neurons
Nerve cells that send messages from the brain to muscles or glands that carry out a response.
What are interneurons
Nerve cells that connect sensory neurons to motor neurons
What does our skin respond through
Pain receptors, temperature receptors and pressure receptors.
Endocrine glands…
- Relesae hormones into the bloodstream.
- Located all around the body
- Influence reproduction, metabolism, growth, ect.
Hormones…
- Affect behavior and emotions
- Stimulate growth and reactions
- Circulate throughout the whole body
- Are produced in glands
Major endocrine glands (10)
Pineal gland, Pituitary gland (master gland), thyroid, thymus, hypothalamus, adrenal gland, pancreas, ovaries and testes.
What controls hormones
External and internal stimuli.
Target Cells
Hormones only work on certain cells, called target cells. The target cells have special receptors that recognize the hormones and allow them to influence that cell. “They ‘fit’ like lock and key”
Definition of negative feedback loop
Means that when enough hormone is in the body, the body stops producing the hormone until it is needed again.