Lecture 2 Flashcards
Different orientation systems (7)
- Superior = above
- Anterior = in front of
- Posterior = behind
- Interior = below
- Rostral = towards the nose
- Caudal from rostral = towards the back of the head.
- Caudal from brain = down the spine
Anatomic orientation
Illustrates the direction of a cut or section through the human brain from the perspective of the viewer.
- Frontal (coronal) view = vertically from ear to ear
- Horizontal (dorsal) view = flat across the brain
- Sagittal (medial) view = lengthways front to back
Cerebrovascular accident (2)
Ischemic CVA (80%)
- Blockage of blood vessel by clot.
Hemorrhagic SVA (20%)
- Burst of vessel bleeding into the brain.
Main structure visible from the outside of the brain
- cerebrum
- cerebellum
- brainstem
The higher a structure is located physically, the ‘higher’ its function.
- meaning it is more complex, more integrated.
Gyrus, sulcus info/measurements
- Gyrus = curve, bend, HILLS
- Sulcus = groove, VALLEYS
- Fissure = deep sulcus
- Total surface area, ~0.25 m^2, ~40 x 62.5 cm
- Width is 2-4 mm
Grey matter
Nerve cells (no insulating layer)
White matter
nerve fibers (insulating layer, fatty myelin)
Ventricle system - general term & function
4 interconnected cavities filled with cerebrospinal fluid (CSF)
- Presumed function = maintaining brain metabolism, excretion of metabolic waste, cushion the brain.
1st & 2nd ventricles
Lateral ventricles
- One in each hemisphere
Third ventricle
Diencephalon
- Between right and left thalamus
Fourth ventricle
- Between the cerebellum and the pons
Telencephalon (endbrain)
- Neocortex
- Basal ganglia
- Limbic system olfactory bulb
- Lateral ventricles
FOREBRAIN
Diencephalon (between brain)
- Thalamus
- Hypothalamus
- Pituitary gland
- Pineal body
- third ventricle
BRAINSTEM
Mesencephalon
- Tectum
- Tegmentum
- Cerebral aqueduct
BRAINSTEM
Metencephalon (across brain)
- Cerebellum
- Pons
- Fourth ventricle
BRAINSTEM
Myelencephalon (spinal brain)
- Medulla oblongata
- Fourth ventricle
BRAIN STEM
Brain tissue consists of 2 types of nerve cells
- Neurons, major brain functions
- Glia, support cells (lit. glue)
Cells are connection through what?
Nerve fibres called axons.
A bundle of nerves within the CNS
Tract
A bundle of nerves outside of the CNS
Nerve
What is inside and outside of the spinal cord
- Inside = grey matter (nerve cells)
- Outside - white matter (nerve fibres (tracts))
- This is the opposite of brain tissue
What are the 5 spinal cord segments
- Cervical
- Thoracic
- Lumbar
- Sacral
- Coccygeal
Each dermatome (body segment) has two spinal (peripheral nerves)
- A sensory nerve (afferent)
- A motor nerve (efferent)
What does the sensory nerve (afferent) do?
Send information from the skin, joints and muscles to the spinal cord.
- Afferent: toward a structure (incoming)
What does the motor nerve (efferent) do?
Control the muscle movements in that particular body segment.
- Efferent: away from a structure (outgoing)
Where are the spinal nerves located?
On the left and right side of the spinal cord (bilateral pairs).
Dorsal/posterior root of the spine
- Sensory (afferent)
- Pain, temperature, touch
Ventral/anterior root of the spine
- Motor (efferent)
- Muscle movement, reflexes
12 pairs of cranial nerves
One set controls the left side, the other set controls the right side of the head.
Olfactory function
Smell
Optic function
Vision
Oculomotor function
Eye movement
Trochlear function
Eye movement
Trigeminal function
Masticatory movements and facial sensation
Abducens function
Eye movement
Facial function
Facial movement and sensation
Audiotry vestibular function
Hearing and balance
Glossopharyngeal function
Tongue and pharynx movement and sensation
Vagus function
Heart, blood vessels, viscera, movement of larynx and pharynx
Spinal accessory function
Neck muscles
Hypoglossal function
Tongue muscles
Bell’s palsy info
Inflamation of the facial nerve (7th cranial nerve)
- Swelling compression, partial loss of nerve function.
- Symptoms: unilateral weakness or paralysis of facial muscles
- Primary cause: viral infection
- Treatment: anti-inflammatory drugs and antiviral agents.
- NB: symptoms are also common in stroke, tumour and trauma
(ANS) sympathetic division stimulation
Activation, arousal (fight or flight)
What is the (ANS) sympathetic division connected to?
Thoracic and lumbar spinal cord segments.
- Ganglia (minibrains) near spinal cord
Preganglionic + postganglionic fibres in sympathetic division
- Found in the sympathetic division
- Preganglionic fibres are short
- Postganglionic fibres are long.
- Acetylcholine = preganglionic
- Norephinephrine = postganglionic
(ANS) parasympathetic division inhibition
Relaxation, digestion (rest and digest)
What is the (ANS) parasympathetic division connected to?
Sacral spinal cord segments, but mostly to three cranial nerves (vagus, facial & oculomotor)
- Ganglia (minibrains) near target organs
Preganglionic + post ganglionic fibres in parasympathetic division
- Preganglionic = long
- Postganglionic = short
- Acetylcholine (both pre & post)
3 parts of the brainstem
- Hindbrain: rhombencephalon (metencephalon+myelencephalon) –> mainly motor functions.
- Midbrain: mesencephalon –> sensory functions.
- Between brain: diencephalon –> integrative sensorimotor tasks
Rhombencephalon (hindbrain)
Metencephalon (across brain)
- Pons + cerebellum
Myelencephalon (spinal brain)
- Medulla.
Reticular formation
Net-shaped mixture of neurons (grey matter) and nerve fibres (white matter)
- Arousal, sleep/awake
- Pons
- Medulla
- Cerebellum
Midbrain (mesencephalon)
Substantia nigra
Between brain (diencephalon)
- Thalamus: integrates sensory input and relays it to appropriate areas of the cerebral cortex
- Hypothalamus (below the thalamus): controls hormone prodiction via pituitary gland & takes part in nearly all aspects of behaviour
Forebrain (basal ganglia)
Control and coordinate voluntary movement act as “volume control” by controlling the force of movements.
NB: substantia nigra and subthalamic nucleus are also part of the basal ganglia.
