The brain and nervous system (wk2) Flashcards
Draw out the diagram of the nervous system
What does the nervous system aim to do?
-The nervous system exists to control movement
Describe the central nervous system
-Everything inside the spine and skull -> cortex, subcortical structures and nuclei, spinal cord
-The structures are encased in bone
-It’s very poor at fixing itself if damaged
Describe the peripheral nervous system
-Everything outside the spine and skull -> nerves (bundles of axons that connect the CNS to the rest of the body) + ganglion (clusters of cells associated with the nerves)
-The PNS can regrow after damage
-Can be thought of as a system of inputs and outputs -> input from the sensory division (afferent), output from the motor division (efferent)
What is the peripheral motor output system (efferent)?
-Somatic -> controls voluntary movement
-Autonomic -> controls involuntary/unconscious movements
-Has 2 components
What is the somatic motor system (efferent)?
-The nerves exit the spinal cord and contact muscles
-Stimulation of these nerves causes contraction of muscles and moves the body
-Controls voluntary movements
What is the autonomic system (efferent)?
-Controls the lungs, heart, smooth muscle, endocrine and exocrine glands
-Two autonomic systems work together to keep internal system in balance
Describe the sensory (afferent) division:
5 basic sensory systems;
-Visual
-Auditory
-Olfactory (smell)
-Gustatory (taste)
-Tactile sensation (touch)
+ Vestibular -> sense of head movement in space
+ Proprioceptive sensations (sensations from the muscles and joints of the body)
Describe how movements are like a circuit:
-Movements tend to be in response to an external stimuli or directed at an external stimulus, however they start with sensory input
1.Sensory input -> receptors monitor changes and info sent by afferent nerves
2.Integration -> information is processed
3. Motor output -> effector organs are activated and effected by efferent nerves
Describe what brains are made of:
-86 billion cells
-The human brain consumes 20% of the total energy generated in the body, although it represents only 2% of the total body weight
-15-20% of the total cardiac output is directed to the brain
-Fluorodeoxyglucose is a marker of the tissue uptake of glucose (found in grey matter uptake, kidney excretion, bone marrow uptake and bladder excretion)
What are the 2 major cell types of the microscopic constituents of the nervous system?
- Neurones -> Electrically excitable cell and communicated with other cells via specialized cells called synapses. They contain; dendrites, nucleus, cell body, axon, myelin and an axon terminal. Information passed through neurones is electrical and the process is called synaptic transmission
- Glial cells -> Non-neuronal cells that maintain homeostasis, form myelin and support/protect for neurones
Name and describe the 5 major types of glial cells:
- Astrocytes -> regulate chemicals and neurones e.g. glucose and regulate blood flow around the brain
- Oligodendrocytes -> form the myelin sheath on axons in the CNS and myelin is a fatty, protein rich sheath that wraps around axons and can myelinate up to 50 axons
- Schwann cells -> form mylein in the PNS, assist in regeneration and regrowth of axons and allows axons to propagate more quickly
- Microglia -> the brains immune system, search the CNS for plaques
- Ependymal cells -> make up a membrane called the ependyma which is a thin membrane lining the central canal of the spinal cord and ventricles
White and grey matter
-White matter -> made of fat and proteins
-Grey matter -> contain the cell bodies of the neurones (nuclei, ganglion, cortex), appear pink, but grey in perfused
Draw the brain and the constituent parts of it:
What are the 5 constituent parts of the brain?
-Cerebrum -> volitional movements
-Tectum -> contains areas that control movements in response to external stimuli
-Cerebellum -> coordination
-Spinal cord/hindbrain -> automatic movements, coordination, breathing, posture, balance, gait