The Nervous System Flashcards
What is the nervous system
Detects and responds to changes inside and outside the body
Coordinates and controls vital aspects of body function and maintains homeostasis
Consists of the brain, the spinal cord and peripheral nerves
What are nerve cells
Is the base part of the nervous system, they link together to form neural circuits, nerves and nervous tissue
What are neural circuits
Groups of neurons that work together to process information and respond, can be simple or complex
What are nerves
Bundles of axons, which are the long nerve cell projections, surrounded by connective tissue
What are nervous tissue
Made up of many neurons bound together by connective tissue, helps control and coordinate the body
What is nerve cell connection and transmission
More than 50 neurotransmitters in the brain and spinal cord including noradrenaline, adrenaline, dopamine, histamine, serotonin, gamma-aminobutyric acid (GABA)and acetylcholine
Other substances such as enkephalins, endorphins and substance P have specialised roles in e.g. transmission of pain signals
Describe the several coverings of protective connective tissue
Endoneurium is a delicate tissue surrounding each individual fibres
Perineurium is a smooth connective tissue surrounding each bundle of fibres
Epineurium is the fibrous tissue surrounding and enclosing several bundles of nerve fibres, covers most large nerves
What is the dura mater
Consists of two layers of dense fibrous tissue
The outer periosteal layer lines the inner surface of the skull bones and the inner layer provides a protective covering for the brain
This provides a thick durable cover for the brain and the spaces between its layers allow for the passage of veins and arteries that supply blood to the brain
What is the arachnoid mater
Thin weblike layer that doesn’t contain blood vessels or nerve tissue, it instead contains cerebral spinal fluid (CSF)
This fluid continuously bathes the entire central nervous system and helps provide nutrients and remove impurities
What is pia mater
Very thin layer that contains many tiny blood vessels that supply blood to the brain tissues
Very delicate later that can’t be directly removed from the brain tissue
Follows the contours of the brain tissue into all the folds and fissures
Describe cerebral spinal fluid
CSF supports and protects the brain and spinal cord
Acts as a cushion or shock absorber
Keeps brain and spinal cord moist
Involved in regulation of breathing
Contains = water, mineral salts, glucose, plasma proteins, small amounts of albumin & globulin, a few leukocytes, small amounts of creatine and small amounts of urea
Describe the cerebrum
Large part of the brain that sits superior to the cerebellum
The two hemispheres are connected by corpus callosum
The flax cerebra is formed by dura mater which penetrates to the depth of the corpus callosum
The cerebral cortex is composed of nerve cell bodies
The surface of the brain has many ridges and furrows called succinct and increases SA
Describe areas of cerebellum
Are linked to our functions and abilities
This doesn’t mean that these areas are the only areas linked to those abilities but does mean that if damaged people are more likely to see side effects too those abilities
What is the contra- lateral control
Motor control lies in frontal lobe
Two neurones are linked to the pathway from the brain to skeletal muscle
The upper motor neurone descends from the motor cortex and through the internal capsule to the medulla oblongata
It crosses here so that the left motor neurone is responsible for the right side of the body and the right motor neurone for the left side of the body
Where is motor/ speech controls
Known as brocas area
Controls speech and muscle movements needed for speech
What is the somato- sensory
Responsible for the sensations of touch, pain, temperature, pressure, awareness of muscular movements and the position of our limbs
What is the wernickes area
Responsible for the perception of language and speech
Describe the thalamus
Deep within the cerebellum
Responsible for arousal and some emotional responses, recognition of touch, pain and temperature and it acts as a relay sending signals from most of the brain to the cerebral cortex and the spinal cord
Describe the hypothalamus
Small but important
Helps control hormones which in turn regulate and control:
- effectors of the autonomic nervous system
- appetite and satiety ( hunger and fullness )
- thirst and water balance
- body temp
- emotional reactions
- circadian rhythms
What are pons
Process information from some cranial nerves e.g. 5th cranial nerve and 8th cranial nerve
Contains the pneumotaxic area that operates in conjunction with the respiratory centre to control respiration
Describe the medulla oblongata
About 2.5 cm long
Lies within the cranium, just above the foremen magnum
Its anterior and posterior surfaces are marked by central fissures
Outer aspect composed of white matter and grey matter
Some medullary nerves relay information from the special senses of hearing and balance to higher centres in the brain
What is the cardiovascular centre in the medulla oblongata
Controls blood pressure and the rate and force of cardiac contraction
Within the CVC the vasomotor centre control the diameter of the blood vessels
The vasomotor centre is stimulated by the arterial baroreceptors, body temp and emotions
What is the respiratory centre in the medulla oblongata
Controls the rate and depth of respiration
From here, nerve impulses travel to the phrenic and intercostal nerves, which stimulate contraction of the diaphragm and intercostal muscles and initiate respiration
It functions in close association with the pneumotaxic area in the pons
What is the reflex centres in the medulla oblongata
Irritants in the stomach or respiratory tract stimulate the medulla oblongata activating the reflex centres
Vomiting, coughing and sneezing are protective reflexes that attempts to expel irritants
Swallowing reflex ensures a safe passage of ingested food
What is the autonomic nervous system
All involuntary body functions are controlled by this
Divided in two = sympathetic and parasympathetic
What is the function of sympathetic system
Fight or flight
Adrenal glands secrete noradrenaline and some adrenaline into the bloodstream in response to sympathetic stimulation
The effects of sympathetic stimulation on the heart, blood vessels and lungs prepare the body for exercise
What is the function of the parasympathetic system
Slows down cardiac and respiratory activity but stimulates digestion and absorption of food and the functions of the genitourinary system
Rest and digest allowing digestion and restorative processes to occur quietly when required
