Lecture 7 (Brain) Flashcards
What is the Central Nervous System composed of? What are its main functions?
- Made up of the brain and spinal cord
- Principal integrator of the sensory input and motor output
- Evaluates incoming stimuli (information)
- Formulates responses to changes that threaten homeostasis
What are the 2 coverings of the Brain and Spinal Cord?
1) Bones
2) The inner coverings = The meninges
What is the meninges that protect the brain called?
Cranial Meninges
What are the 3 layers of the meninges called? Describe each of them.
1) Dura mater : outermost layer, tough dense connective tissue
2) Arachnoid mater : middle layer, made of collagen and elastic fibers (looks like spider web)
3) Pia mater : inner layer, transparent layer of collagen and elastic fiber that sticks to surface of spinal cord, contains numerous blood vessels, situated between arachnoid and pia mater (subarachnoid space = where cerebrospinal fluid circulates)
What is meningitis? What is it caused by?
- Inflammation of the meninges
- Caused by bacterial or viral infections
- Can be fatal if untreated
What are the functions of the coverings of the Central Nervous System?
- Provides a supportive and protective cushion
- Reservoir of circulating fluid that monitors internal environment
- Travels around the brain and the spinal cord
- Travels within the 4 large ventricles of the brain
What is the main component of the CNS?
The Brain
Name the 4 major parts of the brain
- The Brain Stem
- Diencephalon
- Cerebellum
- Cerebrum (Cortex)
What’s the difference between white mater and grey mater?
White mater : myelinated axons, sending signals, found deeper in the brain
Grey mater : cell bodies, neuroglia, unmyelinated axons, process signals, found in outer surface of braon
What is the Brain Stem? Where is it situated?
The part of the brain between the spinal cord and diencephalon.
What are 3 parts of the Brain Stem? Where are they situated?
- Medulla Oblongata (bottom)
- Pons (middle)
- Midbrain (top)
Describe the Medulla Oblongata
Controls the basic life support systems
- Cardiovascular centre = regulates heart rate and blood presuure
- Medullary rhythmicity area = adjusts breathing rate
- Reflex integration center = swallowing, vomiting, coughing, sneezing
Describe the Pons
The pons is a bridge that connects parts of the brain with one another
- Relays information from one side of cerebellum to other
- Relays information up to cerebrum
- Helps control breathing, sleeping, swallowing…
Describe the Midbrain
Connects the pons to the diencephalon.
- Coordinates muscle movement
- Involved with reflexes that control eye movement (visual tracking)
- Center for the “startle reflex”
What are the 3 main regions of the diencephalon?
1) Thalamus
2) Hypothalamus
3) Pineal Gland
Visualize where the thalamus is situated. What is its main function?
Major relay for most sensory impulses from spinal cord to cerebral cortex.
Plays a role in maintenance of consciousness.
Visualize where the Hypothalamus is situated? What is its main function?
- Controls the pituitary glands (Releasing hormones) and produces hormones (oxytocin and ADH)
- Primary connection between nervous system and endocrine system
- Controls the autonomic nervous system = contraction of smooth and cardiac muscle
- Regulates emotional and behaviour patterns
- Regulates eating and drinking behaviour (contains thirst centre)
Visualize where the Pineal Gland is situated? What is its main function?
The body’s biological clock depends partly on the pineal gland by varying the secretion of melatonin
Where is the cerebellum located?
Located posterior to the midbrain and inferior to the cerebrum.
What are the functions of the Cerebellum?
- Receives sensory input from muscles, joints, tendons
- Compares actual movements with intended ones
- Helps produce smooth, coordinated movements
- Help execute skilled motor activities
- Maintains posture and balance
Define Ataxia (Happening in Cerebellum)
Disrupted muscle coordination
Caused by damage to cerebellum or even alcohol
Describe the cerebrum. Where is it situated?
Area of higher brain function (reading, writing, speaking, memories, future plans)
- Outer layer : Cerebral cortex (gray mater)
- Inner layer : white mater
- Surface folds of cerebral cortex : gyri
- Groves between gyri : sulci
- Deep grooves = Fissures
- Longitudinal fissure: divides cerebrum into right and left hemispheres
- Hemispheres are connected by corpus callosum
What are the 4 lobes found in each cerebral hemisphere?
- Frontal
- Occipital
- Parietal
- Temporal
What are the 3 types of functional areas in the lobes?
1) Sensory=receive sensory input (involved in perception of senses)
2) Motor areas=initiation of movement
3) Association areas=integration of information
What are the characteristics of the Frontal lobe?
Primarily motor functions and association areas
1) Primary motor area (motor)
- Control of muscle contraction
- Right side controls left side of body
2) Broca’s speech area (motor)
- Muscle control speech (language)
3) Premotor area (association)
- Prepares sequences of complex muscle contractions
What is the main characteristic of the Occipital lobe?
1) Primary visual area (sensory)
- Responsible for visual perception
What are the main characteristics of the Parietal lobe?
Sensory function and has association areas.
1) Primary somatosensory area (sensory)
- receives sensory input (tactile, T°, pain, itching, tickling)
2) Primary gustatory area (sensory)
- Taste
3) Wernicke’s area (association)
- Responsible for interpretation of speech
4) Common integration area (association)
What are the characteristics of the Temporal lobe?
1) Primary auditory area (sensory):
- responsible for sound and perception of what is heard
2) Primary olfactory area (sensory):
- receives signals relating to smell and perception of smell
3) Auditory association area (association):
- interpretation of sound
4) Wernicke’s area(association):
- also found overlapping into temporal lobe
- responsible for interpretation of speech
What’s the Limbic system?
Consists of a ring of structures on inner border of cerebrum and floor of diencephalon
Called “emotional brain” = plays primary role in pain, pleasure, anger, affection and behaviour
Key function in memory development
Define Hemispheric lateralization. What is the left side more important for? What is the right side more important for?
The hemispheres of the brain have some small differences, both in anatomy and function
Left side: Language, logic, math, science
Right side: Artistic skills, music, spatial and pattern perception
