Chapter 26 ( The Nervous System ) Brain and spinal cord part Flashcards
Why is the nervous system an essential part of an advanced organism?
It allows an organism to react to environmental and internal changes and to make appropriate behavioural modifications.
Organisation of the nervous system?
Picture Learn and Memorise off by heart :)
Function of the cerebrum
Largest part of brain
Consists of 2 hemispheres.
Surface covered by layer of nerve cell bodies - called cerebral cortex (highly folded)
- Controls conscious thought processes, emotional responses, understanding, use of language and intelligent thought (reasoning + ability to draw conclusions)
Left cerebral hemisphere - receives sensory inputs from receptors on right hand side of body. - controls voluntary muscles in right side from motor cortex.
VICE VERSA - The right hemisphere carries out same functions for left side of body.
Brain picture?
Print off, all angles
https://www.google.com/search?q=the+brain+labelled+from+underneath+&tbm=isch&ved=2ahUKEwiP-uKQ8Nn1AhULNBoKHQ-YCGIQ2-cCegQIABAA&oq=the+brain+labelled+from+underneath+&gs_lcp=CgNpbWcQA1D2C1j2C2C9DmgAcAB4AIABUYgBoAGSAQEymAEAoAEBqgELZ3dzLXdpei1pbWfAAQE&sclient=img&ei=Kbr2Yc_BEovoaI-wopAG&bih=821&biw=1440&safe=active&ssui=on#imgrc=Y_uRQwnalIxu7M
Neurones in reflex arc pathway?
Stimulus → receptor -→ sensory neurone → central nervous system (relay neurone) → motor neurone → effector → response
Structural organisation of the nervous system.
DIAGRAM!!!!! ( page 180) of bible, and 1 of notes.
Central nervous system info?
Brain and spinal cord
Peripheral nervous system info
All neurones that connect CNS with rest of body.
Consist of sensory neurones which carry nerve impulses from receptors to CNS. Motor neurones carry impulses away from CNS to effectors.
Further divisions.
Somatic nervous system info
Part of Peripheral NS
- under conscious control
- used for voluntary actions (eg, moving arm)
carries impulses to skeletal muscles
single neurone links CNS to effector cells
Autonomic nervous system info
Part of Peripheral NS
- Works constantly
- Under subconscious control
- Used when body does something automatically without any decision, ie, involuntary
(eg, heartbeat)
-carries nerve impulses to endocrine glands, smooth muscle (indigestive tract and blood vessel walls), cardiac muscle and SAN in RA wall.
Further divisions
Further divisions of autonomic nervous system
Sympathetic
- Fight or flight
- generally increases activity
post ganglionic NT = noradrenaline
Parasympathetic
- Rest or digest responses
- generally decreases activity
post ganglionic NT = acetylcholine
Regions of the brain
Cerebrum Cerebellum Medulla oblongata Hypothalamus Pituitary gland Pons
Functions of the nervous system
Detect stimuli, interpret them, coordinate response
Function of the cerebellum?
Controls coordination of muscles and non-voluntary movement, balance and posture.
Takes sensory inputs from retina and other receptors, eg, spindle fibres in muscles and organs in inner ear.
Function of the medulla oblongata?
Controls autonomic activities in the body
Contains regulatory centres of the ANS
Controls reflex activities
eg, heart rate, breathing rate, blood pressure, peristalsis in gut muscles.
Function of hypothalamus?
Has 2 centres, one controls PNS, once controls ANS
Controls body temperature, osmoregulation, secretion of hormones via pituitary gland.
Monitors composition of blood plasma, so has very rich blood supply.
Produces hormones secreted
controls most homeostatic mechanisms, eg, water balance, temperature, (expect blood glucose levels)
Function of pituitary gland?
Controls most endocrine glands in the body
2 sections:
Posterior lobe - stores and secretes hormones produced by hypothalamus eg, ADH.
Anterior lobe lobe: produces and secretes hormones, eg, FSH.
What is brain damage?
Acquired brain damage (ABD) = any brain injury occurring after birth.
Two types
- Traumatic brain injury
- Non-traumatic brain injury
There are also progressive neurodegenerative diseases, eg, Alzheimer’s, Parkinson’s.
What is a traumatic brain injury?
Occurs following severe blow to head
Eg, road traffic accident, fall, assault
What is a non-traumatic brain injury?
Doesn’t involve severe blow to head
Eg, stroke, infection, anoxic injury.
What are some neuro-imaging techniques
Important in diagnosing ABD Determine location and extent of damage Enable professionals to determine necessary treatment, surgery or rehabilitation required. MRI fMRI CT scans PET scan EEG
Info on MRI scans?
Magnetic resonance imaging scans.
Uses magnetic field and pulses of ratio wave energy to produce images of structures inside body.
Detailed images
Used to detect tumours, strokes, areas of infarction, areas of demyelination in CNS.
Benefits of MRI scans
- Provide better soft tissue contrast than CT
- Provide detailed images ( better than CT)
- Don’t use ionizing radiation, so patients aren’t exposed to harmful effects of radiation.
Disadvantages/ Risks of MRI scans
- Expensive
- Can disrupt body tissues due to exposure to magnetic forces
- some patients may experience claustrophobia
- patient’s have to remain still to produce good quality images, so infants/patients who can’t need to be anaesthetised - causes risks - slow breathing, low BP.
Info on fMRI?
Functional MRI scans
Identifies activity in specific areas of brain due to increase blood flow.
Technique relies on fact that cerebral blood flow and neuronal activation are coupled.
NOT FINISHED
!HFHFGHISUEGFS IFGOS
Info on CT scans?
Computed tomography scans
- Use x rays that penetrate the body to varying extents depending on density of structures.
Black and white images.
-creates detailed cross-sectional images.
- further detail can be obtained by using CT perfusion - injected with substance to show areas that are adequately supplied with blood - better differentiation between tissues - better image.
Advantages of CT scans?
- Painless
- Non invasive and accurate
- Fast, ie, images available immediately
- Ability to image bone, soft tissue and blood vessels at the same time
- Examinations are fast and simple - vital in emergency cases.