Nerve Tissues, Nerve Cells and Nervous Systems Flashcards
1
Q
Define the divisions of the nervous system
A
- Central nervous system – formed by brain and spinal cord which are enclosed in meninges (protective membranes)
- Peripheral nervous system – composed of all other nerve tissue that lie outside the meninges (partly or fully)
Is then divided into: - Somatic nervous system – voluntary, supplies skeletal muscle/connective tissues/skin
- Autonomic nervous system – involuntary, supplies smooth and cardiac muscle
Is then divided into: - Sympathetic nervous system: activates when body is stressed (fight or flight)
- Parasympathetic nervous system: activates when there is little stress (rest and digest)
2
Q
Recall the terminology related to the 4 part brain
A
- Cerebrum (right and left hemispheres)
- Diencephalon (thalamus and hypothamalus)
- Cerebellum
- Brain Stem (made up of midbrain, pons and medulla oblongata)
3
Q
Recall the terminology related to the 3 part brain
A
- Forebrain (telencephalon and diencephalon)
- Midbrain (mesencephalon)
- Hindbrain (metencephalon and myelencephalon)
4
Q
In simple terms, define the functions of the cerebrum and cerebellum
A
- Cerebrum: where intellectual function is processed
- Cerebellum: where motor learning occurs
5
Q
In simple terms, define the functions of the thalamus and hypothalamus
A
- Thalamus: central region of sensory processing
- Hypothalamus: where emotive responses are processed, homeostasis regulated and ANS controlled
6
Q
In simple terms, define the functions of the midbrain, pons and medulla oblongata
A
- Midbrain: sensory and motor processing – particularly movement of the eye
- Pons: involved in the control of breathing and sensations such as hearing, taste and balance
- Medulla oblongata: regulation centre from vital functions (respiration, digestion, heart rate etc)
7
Q
Describe the shape of grey matter in the spinal cord and name the 3 areas of it
A
- H-shape
- Posterior horn, lateral horn and anterior horn
8
Q
What is the role of the meninges
A
• Protection of the brain and spinal cord
9
Q
Define the 3 layers of the meninges
Eg. Dura Mater
A
- Dura mater (outside layer of connective tissue which lines the inner layer of the periosteum)
- Arachnoid mater (impermeable membrane)
- Pia mater (vascular layer)
10
Q
Define neuron and give an account of its main features and functions
A
- Neuron: nerve cell
- Features and function:
-cell body (soma) produces the neurotransmitter
-dendrites to receive messages from other neurons
-axon hillock triggers a depolarisation of the cell membrane of the axon when enough stimulus is given
-axon to carry electrical impulses from cell body to axon terminals so that they can pass the impulse to another neuron
-synapse – chemical junction between terminal of one neuron and the dendrites of another. Releases the neurotransmitter to pass the signal on
*can be myelinated or not by Schwann cells – increases the speed of conduction along the axon
11
Q
Define neuroglia and give an account of its main features and functions
A
- Cells which are located in the CNS and PNS and provide a supporting framework, homeostatic support and defence to nervous tissue
- 4 types within CNS: oligodendrocytes (myelinate many axons), astrocytes (control the microenvironment of neurons and perform metabolic reactions), microglia (immune defence), ependymal cells (form an epithelium like layer that lines spinal cord and ventricles of the brain)
12
Q
Name the four types of neurons
A
- Somatic sensory
- Visceral sensory
- Somatic motor
- Autonomic motor
13
Q
Describe the basic arrangement of motor and sensory nerves
A
- Motor: multipolar - many dendrites enter the cell body and electrical impulse is travelling from spinal cord to the muscle ‘efferent’
- Sensory: can be unipolar or bipolar
-Unipolar: cell body is in the middle of the axon(s) and electrical impulse is travelling from periphery to the CNS ‘afferent’
-Bipolar: not common but are those that form special senses eg. Retinal neurons ‘afferent’
14
Q
Explain the classification of motor neurons
A
- Upper: originate in brain and carry efferent signals to the LMNs – are responsible for influencing the excitability of LMNs (1st relay)
- Lower: have cell bodies located either in cranial nerve nuclei of brainstem or anterior horn of spinal cord - axons innervate the skeletal muscles (2nd relay)
15
Q
Explain the classification of sensory neurons
A
- 1st order: conduct signals from peripheral receptors – ascend in the posterior columns of spinal cord and relay in the nuclei within medulla oblongata
- 2nd order: ascend from medulla to the thalamus but passing through the midbrain
- 3rd order: carries signal to somatosensory portion of the cerebral cortex
