a&p 1: ch. 12 - the central nervous system

What makes up the central nervous system (CNS)?

The brain and spinal cord.

What is cephalization?

Evolutionary concentration of nervous tissue toward the head.

What are the three primary embryonic brain vesicles?

Prosencephalon, mesencephalon, and rhombencephalon.

What does the prosencephalon become?

Telencephalon and diencephalon.

What does the rhombencephalon become?

Metencephalon and myelencephalon.

What does the telencephalon develop into?

Cerebral hemispheres (cerebrum).

What does the diencephalon develop into?

Thalamus, hypothalamus, epithalamus, and retina.

What does the metencephalon develop into?

Pons and cerebellum.

What does the myelencephalon develop into?

Medulla oblongata.

What are the four major regions of the adult brain?

Cerebrum, diencephalon, brain stem, and cerebellum.

What does gray matter contain?

Mainly neuronal cell bodies, dendrites, and nonmyelinated regions.

What does white matter contain?

Mostly axons, especially myelinated axons.

Where is gray matter located in the spinal cord?

In the central H-shaped or butterfly-shaped region.

Where is gray matter located in the cerebrum?

Outer cortex and deeper nuclei.

What are the ventricles of the brain?

Interconnected cavities filled with cerebrospinal fluid (CSF).

What connects each lateral ventricle to the third ventricle?

Interventricular foramen.

What connects the third ventricle to the fourth ventricle?

Cerebral aqueduct.

What lines the brain ventricles?

Ependymal cells.

What are gyri?

Ridges or raised folds of the cerebral surface.

What are sulci?

Shallow grooves between gyri.

What are fissures?

Deep grooves in the cerebral surface.

What divides the two cerebral hemispheres?

Longitudinal fissure.

What divides the cerebrum from the cerebellum?

Transverse cerebral fissure.

What are the five lobes of each cerebral hemisphere?

Frontal, parietal, temporal, occipital, and insula.

What does the central sulcus separate?

Precentral gyrus of frontal lobe from postcentral gyrus of parietal lobe.

What is the cerebral cortex?

Superficial gray matter involved in conscious thought and processing.

What are the three types of cerebral cortical functional areas?

Motor, sensory, and association areas.

What does the primary motor cortex control?

Voluntary skeletal muscle movements.

Where is the primary motor cortex located?

Precentral gyrus of the frontal lobe.

What does the premotor cortex do?

Plans and coordinates learned or patterned movements.

What does Broca's area do?

Controls motor aspects of speech production.

What does the frontal eye field do?

Controls voluntary eye movements.

Where is the primary somatosensory cortex located?

Postcentral gyrus of the parietal lobe.

What does the primary somatosensory cortex process?

Touch and body sensations from skin, muscles, and joints.

What does the somatosensory association cortex do?

Interprets sensory input such as an object's size, texture, and shape.

Which lobe contains the primary visual cortex?

Occipital lobe.

Which lobe contains the primary auditory cortex?

Temporal lobe.

Where is the gustatory cortex?

Insula.

What sensory function is associated with the olfactory cortex?

Smell.

What sensory function is associated with the vestibular cortex?

Conscious awareness of balance.

What does the prefrontal cortex do?

Planning, judgment, working memory, personality, and reasoning.

What does Wernicke's area do?

Helps understand spoken and written language.

What is hemispheric lateralization?

Functional specialization between left and right cerebral hemispheres.

What do association fibers connect?

Different cortical areas within the same hemisphere.

What do commissural fibers connect?

Corresponding regions of the two cerebral hemispheres.

What do projection fibers connect?

Cerebral cortex with lower brain regions or spinal cord.

What is the corpus callosum?

A major commissural fiber tract connecting the cerebral hemispheres.

What is the general role of the basal nuclei?

Help regulate movements and suppress unnecessary motor responses.

What three major structures form the diencephalon?

Thalamus, hypothalamus, and epithalamus.

What is the main role of the thalamus?

Relay and process information headed to the cerebral cortex.

What is the main role of the hypothalamus?

Regulates homeostasis, autonomic functions, endocrine activity, and drives.

What gland is connected to the hypothalamus by the infundibulum?

Pituitary gland.

What gland is part of the epithalamus?

Pineal gland.

What hormone does the pineal gland release?

Melatonin.

What three structures make up the brain stem?

Midbrain, pons, and medulla oblongata.

What do the superior colliculi do?

Coordinate visual reflexes.

What do the inferior colliculi do?

Serve as auditory relay and reflex centers.

Which midbrain region is associated with Parkinson's disease?

Substantia nigra.

What is one main function of the pons?

Relays signals between brain regions and helps regulate breathing.

What are the major autonomic functions of the medulla?

Regulates heart activity, blood vessel diameter, and breathing.

What is decussation of the pyramids?

Crossing of major motor pathways in the medulla.

What are the main functions of the cerebellum?

Coordination, balance, posture, and adjustment of movements.

What is the arbor vitae?

The treelike pattern of white matter in the cerebellum.

What connects the cerebellum to the brain stem?

Superior, middle, and inferior cerebellar peduncles.

What is the main role of the limbic system?

Emotion, motivation, and aspects of memory.

What is the amygdala associated with?

Fear, emotional evaluation, and threat responses.

What is the hippocampus especially important for?

Forming and consolidating new memories.

What is the reticular formation?

An interconnected network of neurons in the brain stem.

What does the reticular activating system (RAS) do?

Maintains alertness and consciousness.

What is declarative memory?

Memory for facts and events.

What is procedural memory?

Memory for skills and learned actions.

What is short-term or working memory?

Temporary, limited-capacity storage of information.

What helps transfer information to long-term memory?

Rehearsal, associations, and an alert or emotionally engaged state.

What is anterograde amnesia?

Inability to form new long-term memories after injury.

What is retrograde amnesia?

Loss of memories formed before injury.

What does an electroencephalogram (EEG) record?

Electrical activity of the cerebral cortex.

Which EEG waves are common in an alert, mentally active state?

Beta waves.

Which EEG waves are associated with a relaxed, awake state?

Alpha waves.

Which EEG waves are associated with deep sleep?

Delta waves.

What are the two major types of sleep?

REM and non-REM sleep.

What are the three meningeal layers from outermost to innermost?

Dura mater, arachnoid mater, pia mater.

What is the dura mater?

The tough, outermost meningeal covering.

What is the arachnoid mater?

The middle, web-like meningeal covering.

What is the pia mater?

The delicate innermost meninx adhering to the CNS surface.

Where does cerebrospinal fluid flow around the brain?

Subarachnoid space.

What produces most cerebrospinal fluid (CSF)?

Choroid plexuses within brain ventricles.

What are the main functions of CSF?

Buoyancy, cushioning, nourishment, and chemical transport.

What are arachnoid granulations?

Projections that help return CSF to venous blood.

What is hydrocephalus?

CSF buildup caused by impaired circulation or drainage, increasing pressure.

What is the blood-brain barrier?

Selective barrier formed primarily by tight junctions in brain capillaries.

What do astrocytes contribute to the blood-brain barrier?

Their end feet help support and regulate capillary barrier function.

What is a concussion?

A brain injury with a temporary change in brain function.

What is a cerebrovascular accident (CVA)?

A stroke resulting from disrupted blood flow or bleeding in the brain.

What are beta-amyloid plaques and tau tangles associated with?

Alzheimer's disease.

What type of neurons degenerate in Parkinson's disease?

Dopamine-producing neurons in the substantia nigra.

What movement disorder is characteristic of Huntington's disease?

Chorea, or involuntary jerking movements.

What are the two main functions of the spinal cord?

Two-way communication with brain and integration of reflexes.

What are the cervical and lumbar enlargements associated with?

Spinal nerves serving the upper and lower limbs.

What is the conus medullaris?

The tapered inferior end of the spinal cord.

What is the cauda equina?

A bundle of spinal nerve roots extending below the spinal cord.