Overview of the Nervous System Flashcards
What are the subcategories of the human nervous system?
The human nervous system is comprised of the central nervous system (CNS) and the peripheral nervous system (PNS)
The peripheral nervous system (PNS) splits off into the autonomic nervous system and the somatic nervous system
The central nervous system (CNS) comprises the brain and spinal cord
The PNS refers to all parts of the nervous system other than the brain and spinal cord- comprises the somatic and autonomic nervous systems
The somatic nervous system is a component of the peripheral nervous system that innervates the skin, joints and skeletal muscle
The autonomic nervous system is a component of the peripheral nervous system that is comprised of sympathetic and parasympathetic divisions
What is the Cerebrum?
The cerebrum is the largest part of the forebrain- comprises the cerebral cortex and several subcortical structures Parts of the cerebral cortex: Frontal lobe Temporal lobe Parietal lobe Occipital lobe
What are sulci, gyri and fissures?
Cerebrum; sulci, gyri and fissures
The cerebrum is noteworthy for its convoluted surface containing ‘bumps’ called gyri, grooves called sulci or, if especially deep, fissures
Precise pattern of gyri and sulci can vary between individuals but many features are common to all human brains
What are the different cerebral cortex parts responsible for?
Frontal lobe Control of voluntary movement Control of behaviour: Attention, planning and decision making Motivation and emotional regulation Parietal lobe Sensory processing an interpretation Proprioception (i.e. equilibrium and balance of the body) Temporal lobe Auditory processing and interpretation (e.g. speech) Memory (formation of long-term memories) Occipital lobe Visual processing and interpretation (e.g. distance and depth perception, colour, object and face recognition)
What is the Hippocampus, its functions and dysfunctions?
Hippocampus is a region of the cerebral cortex embedded deep within the temporal lobe
Functions:
Learning
Memory formation and retrieval
Regulation of hypothalamus-pituitary-adrenal (HPA) axis
Hippocampal dysfunction?
In 1985, Clive Wearing contracted a virus that caused damage o his hippocampus:
Anterograde amnesia- inability to create new memories
Retrograde amnesia- generally unable to recall past memories
What are the basal ganglia and its function?
Subcortical structures; basal ganglia
The basal ganglia refer to a large and functionally diverse set of neural structures embedded deep within the cerebral hemispheres
Primarily involved in regulating movement (initiation and maintenance of movement, inhibit antagonist movements)
What is the diencephalon?
The diencephalon is a division of the forebrain situated between the cerebrum and midbrain- comprises the thalamus and the hypothalamus
What is the thalamus, its functions and dysfunction?
The thalamus is a large collection of nuclei located in the dorsal part of the diencephalon
Different thalamic nuclei each serve unique functions:
Relay between sensory (excluding olfaction) and motor systems and the cerebral cortex
Regulate arousal and pain, mood, motivation and cognitive functions
Synaesthesia:
A blending of information streams can result in synaesthesia:
Hearing colour
Feeling sounds
What is the hypothalamus, its functions and dysfunctions?
The hypothalamus is a small, almond-sized collection of nuclei located directly above the brainstem
Function:
Smaller collection of nuclei with various functions
Homeostatic, reproductive and other diverse functions (e.g. fight or flight response)
Fight or flight response involves the hypothalamus-pituitary-adrenal (HPA) axis–> cortisol and adrenaline release
Hypothalamic dysfunction?
Hypothalamic dysfunction plays a role in a number of conditions:
Hypothyroidism
Hyperthyroidism
What is the brainstem?
The brainstem is the portion of the brain that lies between the diencephalon and the spinal cord- comprises the midbrain, pons and medulla oblongata
What is the function of the midbrain?
Midbrain functions?
Include the control of eye movements, auditory and visual processing
What is the pons function?
Relay of motor information from cerebral hemispheres to the medulla, spinal cord and the cerebellum
What is the medulla oblongata function?
Cardiovascular (e.g. blood pressure) and respiratory homeostasis
Reflexive actions including vomiting, swallowing, coughing and sneezing
What are the different dysfunctions associated with the brainstem?
Brainstem dead- unable to regain consciousness or breath without the support of an artificial life support machine
Loss of blood circulation to all brainstem regions
Locked-in syndrome
Awake and conscious but no means of producing speech, limb or facial movements
Loss of blood circulation to pons
What is the cerebellum and its functions?
The cerebellum (or little brain) is a prominent hindbrain structure- it accounts for approximately 10% of the human brains volume Cerebellum functions? The cerebellum does not initiate movement but detects differences in motor error between an intended movement and the actual movement Aids the motor cortex to produce precise and co-ordinated movement Is the function of the cerebellum conserved? It has been shown that, for example, the cerebellum is important in synchronisation of movement with musical rhythm
What is the structure of the spinal cord?
The spinal cord is situated within the vertebral column, with spinal nerves (part of the peripheral nervous system) communicating with the cord via notches between the vertebrae
Vertebrae (and spinal nerves) are named in accordance with location:
Cervical vertebrae are located in the neck are named C1-C7
Thoracic vertebrae are attached to the ribs and are named T1-T12
Lumbar vertebrae are located in the lower back and are numbered L1-L5
Sacral vertebrae are located within the pelvic area and are numbered S1-S5
What is the structure of a spinal cord segment?
A spinal nerve passes into the vertebral notch and splits into “roots”:
Dorsal root describes a bundle of sensory neuron axons that carry sensory information into the spinal cord
Ventral root describes a bundle of motor neuron axons that carry information away from the spinal cord to striated muscle
A transverse section of the spinal cord also reveals:
Grey matter (compromised of neuronal cell bodies) divided into horns
White matter (comprised of axon bundles) divided into columns
What is the function of the spinal cord?
Spinal cord contains motor neurones that innervate skeletal muscle and allow for movement as well as motor tracts that carry information for motor movement down from the brain
Spinal cord also receives sensory information (e.g. touch, expression, temperature) from the periphery of our bodies and contains pathways by which that sensory information is transmitted to the brain
What are the injuries associated with the spinal cord?
Tetraplegia:
Tetraplegia refers to the full or partial loss of sensation and movement in all four limbs and torso
Caused by damage in the cervical (C1-C7) area
Paraplegia:
Paraplegia refers to the full or partial loss of sensation and movement in both legs ( and torso depending on the location of the lesion)
Caused by damage in the thoracic (T1-T12), lumbar (L1-L5) or sacral (S1-S5) areas
What are the meninges?
The meninges describes the three membranous layers that cover the brain ( and spinal cord)
From superficial to deep, the meninges comprise:
Dura mater
Arachnoid membrane (or mater)
Pia mater
Primary function is in the protection of the brain and spinal cord
Passage of cerebrospinal fluid (CSF)- ventricular system
Support of cerebral and spinal blood vessels- vasculature system
What is the ventricular system of the brain?
The ventricular system comprises a series of interconnected, cerebrospinal fluid-filled spaces that lie at the core of the forebrain and brain stem
The ventricular system comprises:
Lateral ventricles
Third ventricle
Fourth ventricle
Functions are:
Protection of the brain
Transport (e.g. nutrients, waste products)
Other functions include regulation of buoyancy
What is meant but the vasculature of the brain?
Two pairs of arteries supply blood to the brain: the internal carotid arteries and the vertebral arteries:
Anterior circulation is derived from the internal carotid arteries- supplies the forebrain (cerebrum and diencephalon)
Posterior circulation is derived from the vertebral arteries- supplies the brainstem, cerebellum and upper spinal cord
Functions:
Delivery of oxygen (O2)
Removal of carbon dioxide
Transport (e.g. nutrients, waste products)
