Chapter 2 Flashcards
Chapter 2: The Anatomy and Evolution of the Nervous System
The Meninges
3 layers in the CNS: –Dura mater •Hard mother, outermost layer –Arachnoid membrane –Pia mater •Pious mother
Ventricles
Four ventricles:
•2 lateral ventricles
•3rd ventricle
•4th ventricle
Filled with cerebral spinal fluid (CSF)
CSF moves through self-contained and separate circulation system from blood supply
Production of CSF
- Made by choroid plexus (in ventricles)
* Similar composition to clear plasma of blood
Cerebral Blood Supply
Brain ~2% of body mass but uses ~16% of blood
The 2 Divisions of the Nervous System
Central (CNS): brain and spinal cord
Peripheral (PNS): nerves connecting CNS to muscles, organs, and skin.
Efferent Nerves
(Motor) – goes out from CNS to muscles and organs
Afferent Nerves
(Sensory) – goes toward CNS from sensory receptors
Peripheral Nervous System
Somatic: –Cranial nerves and spinal nerves –Somatosensory and skeletal motor Autonomic: –Glands and organs –Sympathetic –Parasympathetic
Somatic Nervous System: Cranial Nerves
–12 pairs
–Exit/enter directly from brain
–Sensory nerves, Motor nerves, and Mixed nerves
Name the 12 Cranial Nerves
- Olfactory
- Optic
- Oculomotor
- Trochlear
- Trigeminal
- Abducens
- Facial
- Auditory
- Glossopharyngeal
- Vagus
- Spinal accessory
- Hypoglossal
Spinal nerves
–31 left/right pairs
Spinal cord has two parallel pathways
Spinal cord has 2 parallel pathways
–Sensory Nerves: Dorsal Root
–Motor Nerves: Ventral Root
Covered by only two layers of Meninges
Outside spinal cord nerves swell to form spinal ganglion
Ventral Root
Motor Nerves
Dorsal Root
Sensory Nerves
Outside the spinal cord nerves swell to form ______.
spinal ganglion
Bundle of Axons in the Central Nervous System
a Tract
Bundle of Axons in the Peripheral Nervous System
a Nerve
Group of Cell Bodies in the Central Nervous System
a Nucleus
Group of Cell Bodies in the Peripheral Nervous System
a Ganglion
Spinal cord damage
Quadriplegic: thoracic and above
Paraplegic: lumbar, sacral, coccygeal
Autonomic Nervous System
Two divisions –Sympathetic –Parasympathetic Involved in regulating four critical bodily states related to survival— i.e., the 4 Fs: –Fighting –Fleeing –Feeding –…..Reproduction
Parasympathetic Nervous System
Rest and digest •Calms body to conserve and maintain energy •Release acetylcholine •Lowers heart rate and blood pressure •Stimulates digestion
Sympathetic Nervous System
Fight or flight •Release adrenaline and norepinephrine •Raises heart rate and blood pressure •Raises blood flow to skeletal muscles •Inhibits digestion
What Develops from the Hindbrain?
- The Metencephalon: Pons and Cerebellum
* The Myencaphalon (Medulla)
What Develops from the Metencephalon?
the Pons and the Cerebellum
Medulla
–Major relay between the spinal cord and brain
–Cranial nerves
–Vital functions:
breathing, heart rate, blood pressure
Reticular Formation: Arousal
Cranial Nerve Nuclei: Various functions
Pons
(the bridge)
–Sleep, arousal, audition, balance
Vestibular Nucleus: Balance and Position Cochlear Nucleus: Sound Raphe Nucleus: Sleep and Arousal Locus Coeruleus: Sleep and Arousal Reticular Formation: Arousal Cranial Nerve Nuclei: Various functions
Cerebellum
Motor coordination, balance, cognition
Myelencephalon
Medulla (Hindbrain)
Mesencephalon
Midbrain
What Develops from the Diencephalon?
The Thalamus and the Hypothalamus
The Forebrain Consists of What 2 Major Divisions?
the Diencephalon and the Telencephalon
Tectum
dorsal half of the midbrain
Tegmentum
ventral half
Cerebral Aqueduct
links the third and fourth ventricles
What separates the Tectum and the Tegmentum of the midterm?
cerebral aqueduct
Superior Colliculi
Guide eye movements and fixation of gaze
Part of the Tectum
Inferior Colliculi
Locate direction of sounds
Part of the Tectum
Reticular Formation
Involved in Arousal
Found in the Midbrain, the Pons, the Medulla
Vestibular Nucleus
Involved in Balance and Position
Periaqueductal Gray
Pain
Located in the Midbrain
Substantia Nigra
Motor function
Located in the Midbrain
Red Nucleus
Motor function
Located in the Midbrain
Diminished Substantia Nigra is seen in what disease?
Parkinson’s disease
Midbrain
Also known as the Mesencephalon.
Red Nucleus: Motor Function
Substantia Nigra: Motor Function
Periaqueductal Gray: Pain
Reticular Formation: Arousal
Cranial Nerve Nuclei: Various functions
Inferior Colliculi: Locate direction of sounds
Superior Colliculi: Guide eye movements and fixation of gaze
What Develops from the Telencaphalon?
Isocortex, Basal Ganglia, Limbic System
Thalamus
–Sensory relay
–Arousal, consciousness
Hypothalamus
−Regulatory center
–Controls pituitary gland
–ANS control
Limbic System
Collection of forebrain structures that participate in emotional behavior and learning
Composed of the Amygdala, the Hippocampus, the Anterior Cingulate Cortex, etc.
Basal Ganglia
- Control of movement
- Parkinson’s and Huntington’s disease
- ADHD, OCD
Neocortex composes what percentage of the human cerebral cortex?
90%
Features of the Cortex
- Gyrus (Hills)
- Sulcus (Valleys)
- Fissure
- Hemispheres
Encephalization Quotient
Ratio of brain size to body size
Humans have the largest EQ, at 7.44
Contralateral Connections
the Corpus Callosum and Anterior Commissure link the 2 hemispheres of the brain
Frontal Lobe
- Forward-most part of cerebral cortex
- Contains primary motor cortex, prefontal cortex, Broca’s area
- Roles in motor function, language, memory, many “advanced” functions
Central Sulcus:
frontal lobe region that separates precentral gyrus from postcentral gyrus
Frontal Lobe: Precentral Gyrus
the Precentral Gyrus is the frontal lobe region that contains Primary Motor cortex and controls Voluntary Body Movement
Frontal Lobe: Prefrontal Cortex
•Functions include: planning and organization, attention, decision making, impulse control
•Phineas Gage
•Implicated in a number of psychopathologies:
–Schizophrenia
–ADHD
–Sociopaths
Parietal Lobe
- Primary somatosensory cortex, association cortex
* Specialized for skin senses and senses that inform us about body position and movement, spatial perception
Association Cortex
areas capable of integrating sensory input with motor output
Postcentral Gyrus
Parietal lobe region that contains primary somatosensory cortex
Temporal Lobe
•Primary auditory cortex, visual and auditory association areas, additional language areas, Limbic system
Medial Temporal Lobe
Location of many Limbic system structures, including amygdala and hippocampus
Occipital Lobe
•Primary visual cortex: where visual information is processed
Pia Mater
The thin innermost layer of the 3 meninges covering the CNS