Lecture 4: Anatomy of the nervous system Flashcards Preview

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Flashcards in Lecture 4: Anatomy of the nervous system Deck (20)
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1

What are the Anatomical directions in the vertebrates?

*Lateral: Towards the side
*Medial: Towards the midline
*Dorsal: Toward the back
*Ventral: Toward the stomach
*Anterior: Toward front end
*Posterior: Toward rear end
*Directions in the cerebral hemispheres rotated by 90' in comparison to those of spinal cord.

2

What is the Midsagittal section?

Section cut down the centre of the brain.

3

What is the Somatic nervous system?

*Interacts with external environment.
*Controls voluntary muscles and conveys sensory information to the CNS.
- Afferent: from skin, skeleton muscles.
- Efferent: Motor signals from CNS to skeleton muscles.
*Conscious and voluntary.

4

What is the Autonomic nervous system?

*Regulates body's internal environment.
*Controls involuntary muscles.
- Afferent: internal sensory signals to CNS.
- Efferent: Motor signals from CNS to internal organs.
*Unconscious and automatic.

5

What is the sympathetic Nervous system?

*Prepares the organs for vigorous activity.
*Increases breathing and heart rate, decreases digestive activity.

6

What is the Parasympathetic Nervous system?

*Promotes energy - conserving, non - emergency functions.
*Generally does the opposite of sympathetic activities.

7

What is the spinal cord?

*Communicates with sense organs and muscles below the head.
*Segmented structure
- Sensory nerves: enter
- Motor Nerves: Exit.
*If cut, brain loses sensation from that segment and all segments below.
*Simple, reflexive behaviours can take place on the level of the spinal cord.

8

What is the function of the Hindbrain?

*Medulla
- Tracts carrying signals between rest of the brain and body.
-Controls some vital reflexes (breathing, heart rate, vomiting).
*Reticular formation
-Plays important role in arousal, sleep, attention, movement, cardiac and circulatory responses.
*Pons
-Axons from each side of the hemisphere cross.
*Cerebellum
- Important sensorimotor structure - coordination of movements.
- Seems also involved in cognitive functions.

9

What is the function of the Midbrain?

*Tectum
-Superior colliculus: visual function.
-Inferior colliculus: Auditory function.
(Dorsal)
*Tegmentum
-Sensorimotor function, part of the system that deteriorates in parkinson's disease.

10

What is the function of the Forebrain - Diencephalon?

*Thalamus
- Sensory relay to the cerebellum (except for olfactory information).
*Hypothalamus
-Important for regulation of motivated behaviours.
-maintanance of homeostasis.
-Regulates release of hormones from pituitary gland.

11

What is the Forebrain - Telencephalon?

*Largest division of the human brain.
*Initiates voluntary movement, interprets sensory input, mediates complex cognitive processes.
*Main parts: cerebral cortex, basal ganglia, limbic system.

12

What is the function of the Forebrain - Telencephalon?
*Basal ganglia

-Several structures that play a major role for voluntary motor responses.
-e.g. pathway from substantia nigra to striatum is deteriorated in Parkinson's disease.
-Electrodes implanted deep inside the brain.
-Targeted brain regions electrically stimulated.
-Result: Reduction of tremor.

13

What is the function of the Forebrain - Telencephalon?
*Limbic system

-Regulates of motivated behaviours.
-Amygdala, hippocampus, cingulate, cortex and others.
*Cerebral Cortex
-Outer surface of cerebral hemispheres
-4 lobes
-Deeply convoluted to increase surface of the cortex
> Large furrows: fissures
> Small furrows: Sulci
> Ridges between furrows: Gyri
-Neurons communicate across hemispheres mainly through the corpus callosum.

14

What is the function of the Forebrain - Telencephalon?
*Occipital Lobe

*Primary visual area
*Destruction of any part of the primary visual cortex causes cortical blindness in the related part of the visual field.

15

What is the function of the Forebrain - Telencephalon?
*Parietal Lobe

*Receive sensation from touch, muscle stretch and joint receptors.
*Lesions often result in hemispatial neglect, (e.g. damage to the right hemisphere causes tendency to ignore the left visual field).
*Not an deficit in perception or sensation, but in attention.

16

What is the function of the Forebrain - Telencephalon?
*Plasticity of the brain

*Somatosensory cortex undergoes substantial reorganisation after the loss of sensory input.
*Can lead to phantom limb sensation.
*Learned adjustments in behaviour.

17

What is the function of the Forebrain - Telencephalon?
*Temporal lobe

*Primary target for auditory information.
*Left temporal lobe relevant to understanding language.
*Medial part: Memory (hippocampus)
*Inferior part: Complex aspect of vision (e.g. facial recognition).

18

What is the function of the Forebrain - Telencephalon?
*Frontal lobe

*Primary motor cortex
-Controls voluntary movement of the body.
*Prefrontal cortex:
-receives and integrates input from all sensory systems.
-Higher cognitive functions (working, memory, planning).
-prefrontal lobotomy - surgical disconnection of the prefrontal cortex from the rest of the brain (1940s/50s)

19

What equipment is used to measure the brain?

*PET - 3D image of the brain.
*fMRI - measures brain activity, looks at blood flow.
*EEG

20

What are the effects of brain damage?

*Damage in the left frontal cortex
-Language impairment
-Discovery of Broca's & Wernicke's areas.
*Problem: few cases and damage rarely localised.
-visual lesion via magnetic stimulation.
-Only temporary.
*The brain is symmetrical (anatomy).
*The brain is asymmetrical (function).
- Split brain research: corpus callosum is severed in some epileptic patient (prevents seizure to travel to the 2nd hemisphere) *Sperry.