Nervous System Flashcards
WRT Neuron:
- Define
- State location
- State function
- the neuron is the structural and functional units of the nervous system.
- They are located in the brain and spinal cord
- They transmit nerve impulses from sense organs to the CNS and from the CNS to the muscles and glands
Characteristics of cyton/Perikaryon
- It contains a well defined nucleus
- Nucleus surrounded by granular cytoplasm
- Has all organelles like other cells, but centrosome is absent as they have lost the ability to divide
Fill in the blanks
The cyton has all cell organelles except _ _ _ _ _
Centrosome
Define and state the function of dendrites.
Dendrites are branched cytoplasmic projections of the cyton
They conduct nerve impulses to the cyton
State the Location and function of myelin/medullary sheath
Location- around the axon of a neuron
Function- Its an insulating sheath which speeds up the rate of transmission of nerve impulses as it travels down the axon
what is a synapse?
the point of contact between the axon bulb of a neuron and the dendrite of the next neuron.
what are the three types of neurons and what do they do?
The 3 types of neurons are: Sensory, Motor and Association neurons
Sensory neurons: Convey impulse from receptor to spinal cord or brain
Motor neurons: Carry impulse from CNS to an effector (muscle / gland)
what are nerves
A nerve is a bundle of nerve fibres of separate neurons enclosed in a tubular sheath
types of nerves
Sensory nerves(contain sensory neurons only) Ex: Optic nerve arising from eye and ending in the brain
Motor nerves (contain motor neurons only) Ex: Nerve arising from the brain and supplying the muscles of the eyeball for rotating the eye
Mixed nerves(contain both sensory and motor neurons) Ex: Spinal nerve
parts of nervous system
- Central nervous system
- peripheral nervous system
- autonomic nervous system
What are meninges? Name them
The three membranous coverings that protect the brain are called meninges
1. Dura mater (outer)
2. Arachnoid (middle)
3. Pia mater (inner)
The inflammation of the meninges is called:
Meningitis
Expand CSF. State its location and function.
Cerebrospinal fluid. It is located in the space between the meninges, ventricles in the brain and central canal of the spinal cord. It acts like a cushion and protects the brain from shocks
The outer cortex of the cerebrum is made of ___________ matter. The inner medulla is made of ________ matter.
Gray ( contains cytons)
White (contains axons)
what is cranial nerves?
the nerves that arise from the brain are called cranial nerves. there are 12 pairs of cranial nerves. cranial nerves supply different parts of head.
what is spinal nerves
the nerves that arise from the spinal cord is the spinal nerve. there are 31 pairs. the spinal nerves have mixed nerves.
what is a reflex action? (2)
it is an automatic involuntary action in the body brought about by a stimulus
what is a reflex arc
The shortest route taken by an impulse from a receptor to an effector.
What is Corpus Callosum? What is its function?
The sheet of fibres connecting the two cerebral hemispheres. Its function is to transfer info from one hemisphere to the other
What are the divisions of the spinal nerves?
8 pairs in neck, 12 pairs in thorax, 5 pairs in lumbar, 5 pairs in sacral and 1 pair in coccygeal region
What are the functions of the spinal cord?
- controls reflexes below the neck
- conducts sensory impulses from the skin and muscles to the brain
- conducts motor responses from the brain to the muscles of the trunk and limbs
What are the functions of the cerebrum?
- Controls all voluntary actions
- enables us to think, memorise, plan, reason etc.
What is the location of the cerebellum? State its functions
- Base of the brain and under the large cerebrum
F: maintains body balance and coordinates muscular activities
State the location and function of the medulla oblongata
L: Base of the skull
F: Controls involuntary actions of the internal organs, ex: breathing peristalsis, beating of heart etc
What does the forebrain consist of?
Cerebrum and Diencephalon (Thalamus, Hypothalamus)
What does the hindbrain consist of?
Cerebellum, Pons, Medulla Oblongata
State the location and function of pons.
L: Centre of the brain below the cerebellum
F: Carries impulses from one hemisphere to cerebellum to the other and coordinates muscle movement on both sides of the body.
State the location of the spinal cord.
L: extends from medulla of the brain down almost the whole length of the backbone to the end at the second lumbar vertebra.
What is a stimulus?
Any changes in the external or internal environment that brings about a response in the body.
What are inborn reflexes?
Reflexes in which no previous experience or learning in required
