The Nervous System Chapter 8

Overview Two major divisions: _____nervous system and _____ nervous system CNS – _____ and spinal cord; located in _____ cavity Spinal cord – conducts sensory info from the _____NS to the _____; conducts motor info from the brain to effectors (muscles and glands); r_____ center Neurons (4:43)

Overview Brain – receives input from the _____ _____ as well as from its own nerves; central processing center White matter – bundles of axons covered with _____ (myelin gives it ________ appearance); found in brain and cord Gray matter – masses of dendrites and cell bodies; not covered with _____ so it appears _______ Three meninges – _____, _____, and _____ maters; CSF in between arachnoid and pia

Blood-Brain Barrier Tight _____ junctions between endothelial cells of brain capillaries Maintains brain _____. The brain must be kept isolated from any changes in the _____, particularly after meals or exercise. Allows essential molecules, such as oxygen and glucose, to pass from the _____ to the CNS but blocks more massive molecules like hormones and neurotransmitters

Blood-Brain Barrier Also prevents most _____ from infiltrating the CNS _____ cells such as lymphocytes, monocytes and neutrophils cannot penetrate this barrier. Prevents full-blown _____ response in the CNS (bad for delicate neural tissue) Creates challenge for biochemists as they develop medicines Why?

BBB BBB animation (1:58) Challenges of the BBB (4:53)

Cerebrospinal Fluid Produced in masses of special _____ called choroid plexuses Three primary functions: Buoyancy for the brain, c_____, chemical stability Located between the _____ and _____ maters Flows uninterrupted through the CNS through the cerebrospinal canal of the spinal cord to the _____ in the _____ then exits CNS through veins draining the brain Constant _____ must be maintained The total volume of CSF in an adult is about _____ ml. CSF is produced at a rate of 600-700 ml per day

The Brainstem Three parts: medulla oblongata, pons, and midbrain Medulla controls _____ functions like breathing, heartbeat, and blood _____; reflex center Pons is the relay station between the _____ and the rest of the CNS; may play a role in _____; works with medulla to regulate _____ rate Why do we dream? (6:30) Midbrain acts as a relay station between _____ and spinal cord or cerebellum; also controls sensory processes

The Brain Cerebellum – “little brain”; c_____, equilibrium and b_____; muscle tone; only 10% of brain but contains more _____ than the rest of the brain combined; _____ working part of the brain; capable of making _____based on previous experiences; enables rest of brain to work more _____ because it can carry out tasks _____ without conscious thought (speech)

The Brain Cerebrum – “brain”; only part of the brain involved in consciousness; largest part; divided into two _____; superficial layer called the _____; cortex is highly folded (increases _____ _____); neocortex (higher intelligence – found only in m_____); contains four distinct areas called _____

The Brain Hypothalamus – maintains ____; center for _____, thirst, emotions, body _____, circadian rhythms; connected to autonomic NS; controls the _____ gland (endocrine system)  Thalamus – sensory and _____ functions; last relay site before info reaches the _____; organizes info and sends it to appropriate areas of the _____ …info reaches the cerebrum

Human Biological Clock (Circadian Rhythms)

Sleep Patterns (Monitored by Josie Harrington’s phone while she slept)

The Brain Cerebrum Corpus Callosum Thalamus Hypothalamus Pituitary Cerebellum Medulla Oblongata Spinal Cord

The Brain Limbic system – includes portions of the thalamus, hypothalamus, and cerebrum Amygdala – memory, emotions, fear Hippocampus – memory and learning; converts _____-_____ memories into _____-_____; associates sensory experiences (like smells) to _____; spatial relationships

Limbic System Man with no memory (3:05) World memory champion - Part 1 (4:58) World memory champion - Part 2 (5:34)

The Spinal Cord Extension of the _____ Ends between L1 and L2 Conducts impulses between periphery and _____ Central canal (extension of brain ventricles) that contains _____ Covered by the three _____ Ascending and descending nerve tracts

Peripheral Nervous System (PNS) Somatic NS – controls _____ movement; acetylcholine is primary _____; includes all the neurons connected with _____ muscles, skin, and sense organs Autonomic NS – controls _____ movement; unconscious processes; maintains _____; 2 divisions: _____ and _____

Autonomic NS Sympathetic division – “_____-or-_____” response; energy generation; inhibits digestion; diverts blood from _____ system and skin to _____ tissue and _____; dilates breathing passages; increases _____ _____; dilates _____ (increased light); norepinephrine, aka, adrenaline Fight-or-Flight (4:30)

Autonomic NS Parasympathetic division – “_____ and _____”; increases blood flow to _____ system; promotes digestion and absorption; constricts _____ _____; slows _____ _____; acetylcholine

Neuroglial Cells (Neuroglia) Schwann cells – named after Theodor _____; only in peripheral NS; form the insulative _____ _____ around axons (like the covering around electrical wires); enable quick _____ of electrical _____ within an _____

Neuroglial Cells (Neuroglia) Nodes of Ranvier – gaps between Schwann cells that increase the conduction of an _____ down an _____; allow impulse to “_____” down the axon Because the axonal membrane is exposed at the node, nutrients and wastes are able to enter and exit the _____.

Neuroglial Cells (Neuroglia) Microglial cells – _____-_____crew; phagocytic; activated after _____ or disease and remove damaged cells or kill invading _____; derived from blood _____ _____ Microglial cell (green) and astrocyte (red) after injury to a blood capillary. The microglial cell extensions surround the injured area.

Neuroglial Cells (Neuroglia) Astrocytes – connect neurons with _____, which means? Integral part of the _____-_____ barrier Most abundant cell in the brain

Neuroglial Cells (Neuroglia) Oligodendrocytes – like Schwann cells, form the _____ _____ around axons Only in the CNS Oligodendrocyte supplying myelin for many axons

Neuroglial Cells (Neuroglia) Ependymocytes – line cavities (_____) within the CNS; assist in production and circulation of _____ with the help of hair-like cellular extensions called _____ Glial cell review (8:00)

The Synapse Vesicles (purple spheres) are filled with _____. At the synapse, the vesicles fuse with the neuron’s cell _____ and release their _____, which are then picked up by receptors on the receiving neuron’s cell _____.