Flashcards in Lecture 12: CNS Part 1 Deck (28):
Describe the process of brain development
1. Neural plate forms from surface ectoderm
2. Neural plate invaginates, forming the neural groove, flanked by neural folds
3. Neural fold cell migrate to form neural crest , which will form the PNS and other structures
4. The neural groove becomes the neural tube, which will form CNS structures
Name the 3 primary brain vesicles
The three primary vesicles give rise to 5 secondary vesicles. What are they?
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Why is found in the telencephalon brain vesicle?
Cerebrum: cerebral hemispheres (cortex, white matter, basal nuclei)
Here the lateral ventricles are found
What is found in the Diencephalon brain vesicle?
Thalamus, hypothalamus, epithalamus
Also the third ventricles are found here
What is found in the mesencephalon
Brain stem, mid brain. The cerebral aqueduct
What is found in the Metencephalon brain vesicle?
Brain stem, pons, cerebellum, fourth ventricle
What is found in the myencephalon?
Brain stem, medulla oblongata, fourth ventricle
Name the major regions of the adult brain?
1. Cerebral hemispheres: right and left
2. Diencephalon: thalamus and hypothalamus
3. Brain stem: midbrain, pons, and medulla
Refer to slide 14 of picture
Regions and organization of CNS.
What is inside the grey matter?
What is inside the white matter?
Grey matter: is found in the cortex (outside layer) of cerebrum and cerebellum. Nuclei in cerebellum and cerebrum
White matter: myelinated axons
Surface of the brain markings:
What are the 5 lobes of the cerebrum
1. Frontal, parietal, temporal, occipital, insula
What is the name of the fissure separating the two hemispheres?
1. Frontal, parietal, temporal, occipital, insula
2. Longitudinal fissure
What is that line which separates the cerebellum from the cortex?
Transverse cerebral fissure
What happens in the cerebral cortex?
It is the site of the conscious mind: awareness, sensory, perception, voluntary motor initiation, communication, memory storage, understanding. Each hemisphere connects to the contra lateral side of the body
Makes up 40% of total brain mass.
There are three types of functional areas: motor, sensory, association
Motor areas. What is the area responsible for?
-have long axons
-allows conscious control of precise, skilled, voluntary movements, controls learned motor skills.
Brocas area: present in one hemisphere, and is a motor speech area which directs muscles of tongue, active when we speak
What is the sensory area responsible for?
Ie name each of the sensory functions and their roles in receiving sensory information.
Refer to slide 23 for good image
-visual areas: on occipital lobe, receives visual info from retinas
-auditory areas: temporal lobes, interprets information from inner ear as pitch, loudness, and location
-olfactory cortex: medial aspect of temporal lobes, region of conscious awareness of odors
-gustatory cortex: involved in perception of taste
-vestibular cortex: responsible for conscious awareness of balance (positions of head in space)
Visceral sensory area: conscious perception of visceral sensation eg upset stomach, or full bladder
What is it responsible for?
-receives sensory information from the skin,nskeletal muscles, and joints
-capable of identifying body regions being stimulated
-determines size, texture, and relationship of objects being touched
What is the prefrontal cortex function as?
-most complicated cortical region
-involved with intellect, cognition, recall, and personality
-contains working memory needed for judgement, reasoning, persistence and conscience
-development depends on feedback from social environment
What does the limbic system function as?
Provides emotional impact that helps establish memories
What is Basal ganglia (nuclei). What is its functions?
Basal ganglia are areas of grey matter within the white matter.
-influence muscular control
-help regulate attention and cognition
-regulate intensity of slow or stereotyped movements
-inhibit antagonistic and unnecessary movements
Refer to slide 32 for picture
Diencephalon: has three structures. What are they were are they located?
2. Hypothalamus: has a stalk called the infundibulum which connects it to the pituitary
3. Pineal gland: extends from the posterior boarder and secretes melatonin: helps regulated sleep/ wake cycles
What is the function of the hypothalamus?
-the autonomic control centre for many visceral functions (eg blood pressure, rate and force of heart beat, digestive tract motility
-centre for emotional response
-regulates body temperature, food intake, water balance, and thirst
-Regulates sleep and wake cycle
- controls release of hormones by the pituitary
-produces posterior pituitary hormones
What are the functions of the thalamus
-the 'relay' station of the brain. It is the gateway to the cerebral cortex. It sorts, edits and relays information such as:
-afferent impulses from all senses and all parts of the body
-impulses from the hypothalamus for regulation of emotion and visceral functions
-impulses from the cerebellum and basal nuclei to help direct the motor cortices
-mediates sensation, motor activities, cortical arousal, learning and memory
It's is 80% of the Diencephalon
Superolateral walls of the third ventricle
-nuclei project and receive fibres from the cerebral cortex
Draw the peripheral nervous system pathway
What the 6 classification types of stimulus? Explain
Mechanoreceptors: responds to touch, pressure, vibration, stretch, itch
Thermoreceptors: sensitive to changes in temperature
Photoreceptors: respond to light energy eg retina
Chemoreceptors: responds to chemicals eg smell, taste, changes in blood chemistry
Nociceptors: sensitive to pain
Proprioceptors: respond to stretch in skeletal muscles, tendons, joints,ligaments, and connective tissue coveting of bones and muscles and inform the brain of movements
Structure of a nerve. What are the 3 connective tissue coverings called and where are they located?
Endoneurium: loose connective tissue that encloses axons and their myeline sheaths (most deep)
Perineurium: coarse connective tissue that bundles fibres into fascicles
Epineurium: tough fibrous sheath around a nerve
Classification of nerves
Most nerves are mixtures of afferent and efferent fibres and somatic and autonomic (visceral) fibres
Types of fibres in mixed nerves:
Somatic: afferent and somatic efferent
Visceral afferent and visceral efferent
Peripheral nerves classified as cranial or spinal nerves
Ganglia (within PNS): contain neural cell bodies associated with nerves.
Dorsal root ganglia (sensory, somatic)
Autonomic ganglia (motor, visceral)
Cranial nerves: 12 pairs of nerves associated with the brain
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