✅Organisation Of The Nervous System 1 Flashcards
What does the nervous system include?
All neural tissue in the body
How many kinds of cells does neural tissue contain?
Two
What are the two kinds of cells in neural tissue?
- neurons
- neuroglia
What are neurons?
Cells that send and receive signals
What are neuroglia (glial cells)?
Cells that support and protect neurons
What are the organs of the nervous system?
- Brain and spinal cord
• Sensory receptors of sense organs (eyes, ears, etc.) - Nerves connect nervous system with other systems
What are the three main functions of the nervous system?
• Directs immediate responses to stimuli
• Coordinates or moderates activities of other organ systems
• Provides and interprets sensory information about external conditions
What are the two anatomical divisions of the nervous system?
Central (CNS)
Peripheral (PNS)
What is the CNS made up of?
• Consists of the spinal cord and brain
• Contains neural tissue, connective tissues, and blood vessels
What does the PNS consist of?
• Includes all neural tissue outside the CNS
• Functions of the CNS are to process and coordinate what?
• Sensory data from inside and outside body
• Motor commands control activities of peripheral
organs
(e.g., skeletal muscles)
• Higher functions of brain: intelligence, memory,
learning, emotion
What are the primary functions of the brain?
• Perform complex integrative functions.
• Controls both voluntary and autonomic activities.
What are the primary functions of the spinal cord?
- Relays information to and from brain.
• Performs less-complex integrative functions. - Direct many simple involuntary activities.
What are the functions of the PNS?
• Deliver sensory information to the CNS
• Carry motor commands to peripheral tissues and systems
What are nerves? ( also called peripheral nerves)
Bundles of axons with connective tissues and blood vessels
What do nerves do?
Carry sensory information and motor commands in PNS
• Cranial nerves – connect to brain
• Spinal nerves – attach to spinal cord
What does the afferent division of the PNS do?
• Carries sensory information from PNS sensory receptors to CNS.
What do the receptors in the afferent division of the PNS do?
• Detect changes or respond to stimuli
• Neurons and specialized cells
• Complex sensory organs (e.g., eyes, ears)
What does the efferent division of the PNS do?
• Carries motor command from CNS to PNS muscles and glands.
• These target organs, which respond by doing something, are called Effectors.
What do effectors do?
Respond to efferent signals
Cells and organs
How do you distinguish the difference between afferent and efferent?
associate the ”a ” in afferent with the “a” in accessing, and the “e” in efferent with the “e” in exiting.
What are the two sections of the efferent division?
The somatic nervous system (SNS)
The autonomic nervous system (ANS)
What does the SNS do?
• Controls voluntary and involuntary (reflexes) skeletal muscle contractions
What does the autonomic nervous system do?
• Controls subconscious actions, contractions of smooth muscle and
cardiac muscle, and glandular secretions
• Sympathetic division has a stimulating effect • Parasympathetic division has a relaxing effect
What are the basic functional units of the nervous system?
Neurons
Where are the multipolar neuron common?
In the CNS
What are the structure of the multipolar neuron?
Cell body
Short, branches dendrites
Long, single axon
What is the structure of the cell body
• Large nucleus and nucleolus
• Perikaryon (cytoplasm), surrounding the nucleus
• Mitochondria (produce energy)
• RER ”Rough Endoplasmic Reticulum” and ribosomes (produce neurotransmitters)
What is the structure of dendrites?
- Highly branched
- Dendritic spines
• Many fine processes
• Receive information from other neurons - 80–90 percent of neuron surface area
What is the structure of of the axon?
• Is long
• Carries electrical signal (action potential) to target • Axon structure is critical to function
What is the synapse?
• Area where a neuron communicates with another cell
What are the two cells in each synapse?
1- Presynaptic cell
• Neuron that sends message
2- Postsynaptic cell
• Cell that receives message
What does the communication between cells as a synapse mostly involve?
the
release of chemicals call Neurotransmitter by the Synaptic Terminal.
What are neurotransmitters?
Chemical messengers
Where are neurotransmitters released?
At presynaptic membrane
What to neurotransmitters affect?
Receptors of postsynaptic membrane