Topic 10 - Nervous System 1 Flashcards
Learning objectives
- Define the terms, Periferal and autonomic NS
- Descibe the basic structure of a neuron and how it relates to function at the cellular level, and the level of networks within the nervous system
- Explain the relation between neurons and nerves
- List the components of the central, peripheral and autonomic NS and general description of their roles
- Describe the basic structure of the autonomic NS and its role regulating body function
- Provide a general description of the architecture of the central NS and provide a brief overview of the function of each of the significant parts
- Briefly descibe the organisation of the cental NS in terms of lobes and tracts
- Provide a general description of the architecture of the peripheral NS
- Describe the function of the autonomic NS with regard to the sympathetic and parasympathetic divisions and discuss differences in the organisation of the 2 divisions
Central NS
- Brain (Issues commands)
- Spinal Chord (Mainly relaying commands)
Peripheral NS
Cranial Nerves
Spinal Nerves
Understand the feedback loop mechanisms of the different pathways
In notes
Afferent pathway
From Receptors to Controller CNS
* Apart of sensory division of PNS
Efferent Pathways
From Controller CNS to Effectors
- Apart of the motor division of PNS
The Brain parts
Forebrain
Hindbrain:
- Brain Stem & Cerebellum
- Midbrain
- Pons
- Medulla Oblongata
Cerebral Cortex
- Left and Right Hemispheres
- Frontal, Parietal, Occipital, Temporal
Forebrain
Largest region
Contains:
* Cerebral Cortex
* Thalamus
* Hypothalamus
* Pineal Gland
* Limbic system
Hindbrain roles
Brainstem & Celebellim
- Brainstem contains midbrain, pons and medulla oblongata
Midbrain
- Connects brainstem to cerebral cortex
Pons
- “Bridge” between midbrain and medulla oblongata
Medulla Oblongata
- Brain transition into spinal chord
- Contains respiratory and CV control centres
Cerebral Cortex
Left and Right Hemispheres
- Connected by the corpus callosum
Each hemisphere has 4 lobes
-Frontal, Parietal, Occipital, Temporal
Frontal lobe function
Higher executive functions such as emotional regulation, planning, reasoning, problem solving
Parietal lobe function
Intergrating sensory info, touch, temperature, pressure, pain
Temporal lobe function
Processing sensory info, hearing, recognising language, forming memories
Occipital lobe function
Major visual processing centre
Brain lobe locations
Frontal (Front)
Parietal (Top)
Temporal (Bottom/ temple)
Occipital (Back)
Thalamus function
Processes sensory info
Hypothalamus
- Control centre of autonomic NS
- Involved in some hormone activity
- Connects hormones and NS
- Regulates homeostasis
Pineal gland
Produces melatonin to regulate sleep-wake cycles
Involved with hormone functions
Limbic System
- Regulates behavioral and emotional responses
- Hippocampus and amygdala
Basil Ganglia
- Control of voluntary motor movements
- Habit learning
- Eye movement
- Cognition
- Emotion
Cerebellum
- Coordinates gait (how we walk)
- Maintains posture
- Controls muscle tone & voluntary muscle activity (unable to innate contractions)
Receives info about voluntary movement from cerebral cortex and muscles, tendons, joints.
Receives info about balance from vestibular nuclei.
Damage to the cerebellum results in a loss of control of fine movements, posture maintanance and motor learning.
Has different lobes and functions
Brainstem
- Connects forbrain to the spinal chord and cerebellum
- Contains many ascending and descending tracts for relaying info
- Responsible for breathing, conciousness, blood pressure, heart rate and sleeo
Anatomy of Brainstem
- Midbrain
- Pons/Medulla oblongata
- Pons
- Basilar artery
- Vertebral arteries
In Notes
Order of a message from Cerebral Cortex
- Cerebral Cortex
- Thalamus, Hypothalamus, Limbic System, Basil ganglia
- Cerebellum (When fine motor skill involved)
- Brain stem
- Spinal Chord
Sensory and Motor pathways differ. In Notes
Spinal chord
- Carries motor and sensory signals between the brain, periphery and coordinates reflexes
- Organised into segments with pairs of spinal nerves emerging from each segment
Composed of grey matter and white matter
- White matter = fiber tracts of myelinated sensory and motor axons
- Grey matter = Cell bodies
White matter relays messages with descending tracts (motor)/ ascending tracts (sensory).
Decussation
Where pathways cross from one side of the body to the other
- Each cerebral hemisphere receives info from opposite sides of the body.
Spinal Nerves
Contain:
- Dorsal Route (Afferent pathway)
- Ventral Route (Efferent pathway)
- Come together to form the spinal nerve
In Notes
Peripheral Nerves
Large anatomical nerves formed when spinal nerves coalesce
- Made up of motor and sensory fibers.
Dermatomes
Every part of the body is mapped out to a set of spinal nerves
- This can easily help diagnose which nerves may be damaged, depending on the area of skin
See Notes diagram
Cranial Nerves
- Peripheral Nerves connected to brain and brainstem directly
- Serve functions of the head
- Breaks down into specific nerves which control specific functions
Autonomic NS
Functions without concious control to maintain homeostasis
Controls:
- Cardiac muscle
- Smooth muscle
- Exocrine glands
- Endocrine glands
- Divides into sympathetic and parasympathetic NS
Sympathetic NS
‘Fight or flight’
Related to the adrenal gland with the release of epinephrin
Parasympathetic NS
‘Rest and digest’
- Allows more digestion by contolling the blood flow to organs.
