Nervous system Flashcards
Nervous system is split into…
CNS Central Nervous System
PNS Peripheral Nervous System
What is included in the CNS?
Brain
Spinal cord
Functions of brain (CNS) (2)
Coordinates body functions
Input from sensory nerves: processing and reaction
Brain location
Cranial cavity
Takes up entirety of space
3 sections of Brain composition
Forebrain
Midbrain
Hindbrain
Structure of forebrain
Cerebrum
Thalamus
Hypothalamus
Structure of midbrain
Connective stem between forebrain and hindbrain
Structure of hindbrain
Cerebellum
Pons
Medulla Oblongata
4 sections of each hemisphere of cerebrum
Frontal
Parietal
Occipital
Temporal
Deep folds of the cerebrum (3)
Gyri (up-folds)
Sulci (shallow folds)
Fissures (deep crevices)
Thalamus - Function
Processes info received from sensory organs and relays to the cerebrum
Hypothalamus - Functions (2)
- Connects the nervous to endocrine system
- Key role in homeostasis & temp control
Midbrain - Function
Carries info of sight & sound
Cerebellum: Structure
2 hemispheres and deeply fissured
Cerebellum: Location
In hindbrain caudal to cerebrum
Cerebellum: Function
- Controls balance, precision and co-ordination
- Receives info from sensory system
Pons - Structure
S: Bridge between hemispheres of cerebellum
Pons - Location
In hindbrain - ventral to cerebellum
Pons - Function
F: Controls respiration, intensity, depth and frequency
Medulla Oblongata: Location
In hindbrain (from pons to spinal cord)
Medulla Oblongata: Function
- Controls respiration & circulation & blood pressure
- Plays part in swallowing and digestion
Meninges - structure
3 membranes round brain & spinal cord
(Dura, Arachnoid, Pia)
Meninges layers
Dura - Outer - Tough fibrous
Arachnoid - Middle - Collagen fibres & blood vessels
Pia - Inner - Fine layer closely attached 2 brain
Meninges Functions
Protect CNS from mechanical damage
Blood supply & maintain for CSF to nourish CNS
Cerebrospinal Fluid
Nutrition to nervous tissues
Help protect CNS
Blood brain barrier
Complex layer round brain’s blood capillaries
Protect brain from harmful substances
Neurons
Cell that carry info messages or signals to and from the brain & rest of the body
Messages sent by neurons
Nerve impulse or action potentials
3 main types of nerves
Afferent = sensory nerves - signal from sensory neurons to CNS
Efferent = motor nerves - signal from CNS to muscles/glands
Mixed: receives sensory info & send info to muscles
Nerves are also classified as…
spinal or cranial nerves
Spinal nerves
Connect to the spinal cord
Transmit signals to most of the body
Cranial nerves
Found in brainstem
Responsible for signals to the brain
What is the peripheral nervous system made up of?
All nerve and nerve cells outside the brain and spinal cord
Olfactory cranial nerve
Smell
Optic cranial nerve
Visual info
Oculomotor cranial nerve
Movement of the eye
Trochlear cranial nerve
Movement of the eye
Trigeminal cranial nerve
Face (sensory)
Jaw muscles (motor)
Abducens cranial nerve
Movement of the eye
Facial cranial nerve
Face (sensory)
Facial expression (motor)
Vestibulocochlear cranial nerve
Vestibular apparatus of brain
Cochlear branch/ Hearing
Glossopharyngeal cranial nerve
Taste buds (sensory)
Muscles of tongue (motor)
Vagus cranial nerve
Larynx (sensory)
Heart rate
Muscles of gastro-intestinal tract
Accessory cranial nerve
Muscles of neck & shoulder
Hypoglossal cranial nerve
Tongue muscles
12 cranial nerves
Olfactory
Optic
Oculomotor
Trochlear
Trigemenial
Abducens
Facial
Vestibulocochlear
Glossopharyngeal
Vagus
Accessory
Hypoglossal
3 sensory cranial nerves
Olfactory
Optic
Vestibulocochlear
4 mixed cranial nerves
Trigemenial
Facial
Glossopharyngeal
Vagus
5 motor cranial nerves
Oculomotor
Trochlear
Abducens
Accessory
Hypoglossal
Spinal nerves
Leave the spinal cords directly
Carry signals into and away from spinal cord
Somatic nervous system
Conscious (voluntary) control of skeletal muscles of body
Autonomic nervous system
Unconscious (involuntary) control of various systems of the body
2 branches: sympathetic & parasympathetic
Sympathetic Nervous System
Fight, flight or fright
Parasympathetic Nervous System
Rest & Digest
Composition of spinal nerves
Dorsal root: signals towards spinal cord
Ventral root: signals away from spinal cord
Reflex arc (5 components)
Receptor
Sensory neuron
Interneuron
Motor neuron
Effector
Reflex arc
Give fixed, involuntary response to given stimulus (4 protection)
Carry nerve impulses from receptors to spinal cord/ brain and immediately out via motor neurone to cause effector to initiate response
Don’t involve conscious centres of brain
Examples of reflex arc
Withdrawal
Blink
Cough
