Anatomy and Physiology of Brain and Nervous System Flashcards
Anatomy
Refers to Structure
Physiology
Function
Central Nervous System
- consists of brain and spinal cord inter neurons
- Spinal cord is an extension of brain stem, co-ordinates reflexes, channels communication between brain and peripheral nerves
- brain is decision making of CNS
Peripheral Nervous System
Carries information b/w CNS and rest of the body
Made up of all nerves and ganglia outside of CNS
- divided into Somatic NS & Autonomic NS
Somatic Nervous System
Conveys sensory info to CNS and motor msgs to muscles
Gathers sensory info from sense organs and sends to brain
Autonomic Nervous System
- Involuntary
- Regulates involuntary, bodily functions
- Connects to the CNS via nerves to internal organs
- Subdivisions are sympathetic and Parasympathetic
Sympathetic
Dominates when under stress
Activates internal muscles to act quickly
e.g. pupils dilate, released endorphins
Parasympathetic
- Maintains steady state of balanced normal functioning
- Restores body to calmness post threat
- opposite to sympathetic
PNS Nerves
- 31 pairs of spinal nerves
- 12 pairs of cranial nerves
- Dorsal Root: sensory info.
- Ventral Root: Motor info.
Frontal Lobe
- Primary Motor Cortex
- Most complex behaviours: planning, problem solving etc
Control of voluntary movement - Left part = Broca’s area which control muscles of throat, tongue, mouth jaw face
Parietal Lobe
- Primary Somatosensory cortex
- Processes: sensory info, motion detection, depth perception, sense of touch
Occipital Lobe
- Primary Visual Cortex
- Processes inc. visual sense info
- Seeing colours, perceiving and recognising objects
Temporal Lobe
- Primary Auditory Cortex
- Processing sound
- Processes auditory information
- Memory, facial recognition, object identification, emotion
broca’s Area and Wernicke’s Arca
- Responsible for speech production and language processing
- Damage to B.Area: slowed speech, prevent person from speaking, inability to understand language
- Damage to W.Area: Loss of ability to understand language, speak clearly but string of words make no sense
External Recordings: EEG
- Detects, amplifies and records electrical activity of neurons
- Produces a recording of brain waves, are analysed and then interpreted
- Different brain waves detected
- Can indicate tumors, epilepsy, sleeping problems
EEG advantages and disadvantages
adv. = painless, harmless, non invasive, cheap, can be used on all ages
limitations = doesnt detect location of electrical activity
- provides an overview and not a source
Scanning techniques: Still pictures CAT
- Computerised Axial Tomography
- Scanned images is turned into 3D image of brain
- Can detect: tumors, strokes, other injuries
- Can show difference between dmgd & healthy tissue
Advantages and Disadvantages of CAT
- Less expensive brain research method
- Non-invasive
- Some require injection of iodine dye
- dis: exposure to radiation
- provides info about structure, not brain activity
Scanning Techniques Still Pictures: MRI
- Magnetic Resonance Imaging
- Uses magnetic field to create detailed image of brain
- Detects: tumors, abnormalities
Can distinguish types of tissue more clearly than a CT
Advantages and Disadvantages of MRI
Adv. = shows difference between dmgd and healthy tissue
- damages areas easily identified
- non invasive
- no exposure to radiation
Limitations: - no info on brain activity, expensive, no magnets in machine
Scanning Techniques Dynamic Pictures: FMRI
- Functional magnetic resonance Imaging
- Measures brain function during consumption of 02 by neurons
- Higher brain activity means higher oxygen intake?
- Uses large magnets to create magnetic field
- Able to detect flow of oxygenated blood to brain, as oxygen moves to active areas
BOLD: Blood Oxygenated Level Dependent Signal
- Higher BOLD = Increase brain activity = Increase oxygen
Advantages and Disadvantages of FMRI
Adv. = Non-invasive, no radiation, displays active areas of brain
Limitations= Most expensive, small movements affect results
Scanning Techniques Dynamic Pictures: PET
- Positron emissions Tomography
- Glucose consumption of brain
- Higher glucose levels reflect higher brain activity
- Radioactive trace that decays by emitting a positron is injected to body
- Requires injection of radio-active glucose
- Measures amount of brain activity that occurs while participant is undergoing task
USED WITH MRI
- Can detect tumors, other damage, areas of brain linked with reading, maths
Advantages and Disadvantages of PET
Adv: - shows area of brain that is damaged
disadvantages: - invasive procedure, exposure to radiation, does not provide detailed images of the brain
Case Study: Phineas Gage
Suffered accident 4;15 @ 13/09/1848 in USA
- Filling a deep rock with gunpwoder, large rod shot through his head afterward because gun powder was ignited
Striked him below his left eye then going straight through
- Personality changed to impatient, dishonest, crude, irresponsible, profane
- Lived for a while afterwards.
Animal Research
- Studying animals allows one to make predictions about brain function / behaviour in humans
- Results can be generalised
- Researches can manipulate / control environments of animals, study and see affects
Ablation - Karl Lashley
- Contributed for studying, learning and memory
- Surgically removed rats brains but could not find 1 part for memory, therefore memory is not localised to 1 area
- Can be assumed memory is widely distributed through cerebral cortex
- Brain is more complicated than initially thought
Lesions - Sperry
Area of the brain is destroyed / stimulated observing charges
- Two hemispheres of the brain each contain consciousness
- Each hemisphere is responsible for performing different tasks
Electrical Stimulation
- Procedure
- Using multiple micro-electrodes in specific areas of the brain
- Weak electrical currents used in short pulses intended to mimic natural flow of impulses through neural pathways
- 1954 James Odis and Peter Milner
- A rat would press a bar to recieve a small electric shock
- Beneficial effects in anxiety, depression, insomnia and stress
Neurons
- Individual nerve cells that receives, transmits and processes information
- Conveys msgs to each other in the form of neural impulses, electrochemical msgs
- Are the basic building blocks of nervous system
Nucleus of Neurons
control centre
Cell body of Neurons
contains nucleus
Dendrites of Neurons
Receive msgs from other neurons, transmits them towards cell body for processing
Axon of Neurons
Carry information away from cell body
Myelin Sheath
Insulates and protects axons
- speeds up electrical signals
- Neurons do not physically connect to another
Synapse
- Gap between dendrites and axons in neurons
- Chemicals are released here
Neurotransmitters
- Chemical substances that carry msgs across the synapse to the dendrite
- Affect how messages are passed b/w neurons
- Exercise increases neurotransmitters
Motor Neurons
- convey messages away from brain to skeletal muscles for movement
Sensory Neurons
Carry messages to brain to be interpretted
Serotonin
Involved with the onset of sleep and moods
- used in medication for people suffering depression
Dopamine
- Involved in complex bodily movements
- Regulates emotional responses i.e pleasure and excitement
- Used in med. for people with Parkinsons
