Lecture 3 PSYC 2P36

Summary

Divisions

Central and Peripheral

Somatic & Autonomic

Afferent & Efferent Nerves

CNS

Brain & Spinal Cord

receives sensory data from the body, processes that information, and sends out instructions to direct physical actions and internal processes

PNS

• Somatic and Autonomic

• Afferent and efferent nerves

• PARA AND SYMP

connects your central nervous system (the brain and spinal cord) to the rest of your body, acting as a communication network to send sensory input and motor commands

Somatic

External

• Afferent

  • Skin, Muscles, Eyes, Ears

• Efferent

  • Muscles

manages voluntary movements of skeletal muscles and relays sensory data,

Autonomic

• Internal

  • Afferent

    • Internal Organs

  • Efferent

    • Interal Organs

• Branches into Sympathetic & Parasympathetic systems

• automatically and unconsciously regulates vital internal body processes, such as heart rate, blood pressure, digestion, and body temperatur

Sympathetic

Activation

body for stress, danger, intense exercise, or emergency situations

Parasympathetic

Relaxation

Cranial Nerves

Specific Sensory / motor functions

12 pairs - split to two sides of the body

relay sensory, motor, and autonomic signals to and from the head, face, neck, and torso

Meninges

• Dura mater

• Arachnoid

• Pia mater

Cerebrospinal Fluid - CSF

• Protects brain

• Transports nutrients

• Drains waste products

Ventricles

2 Lateral, Third, Fourth,

produce, store ns circulate csf

Cerebral Acqueduct

Hydrocephalus, medical condition, excess csf

channel in the midbrain that connects the third ventricle to the fourth ventricle

Blood-Brain Barrier

• Composed of tightly packed cells in blood vessels

• Protects the brain, impeding passage of certain molecules

• Large molecules require transporters - ie, glucose

  • Impairment of the BBB is associated with neurological conditions

Anatomy of a Neuron

External Features

• Cell membrane

• Cell body

• Dendrites

• Axon Hillock

• Axon

• Myelin

• Nodes of Ranvier

• Buttons

• Synapses

Multipolar Neuron

Has multiple dendrites and an axon extending from cell body

4 Classes of Neurons

• Unipolar

• Bipolar

• Multipolar

• Multipolar Interneuron

Internal Features of a Cell Body

• Nucleus

• Mitochondria

• Endoplasmic reticulum

• Cytoplasm

• Golgi complex

• Cell membrane

  • Microtubules

Neuron Cell Membrane

• Channel Proteins

• Signal Proteins

• Lipid Bilayer

*Cell membrane is a lipid bilayer with signal proteins and channel proteins embedded

Internal Features of a Neuron - Buttons

• Synaptic Vesicles

• Neurotransmitters - inside vesicles

Neuroanatomical structure terminology

Nuclei

• Clusters of cell bodies in CNS

Ganglia

• Clusters of cell bodies in the PNS

Tracts

• Bundles of axons in CNS

Nerves

• Bundle of axons in PNS

Glial Cells

• Oligodendrocytes

  • Myelination in the CNS

Schwann Cells

• Myelination in the PNS

Microglia

• Immune system responsibilities

• Role in cell death, synapse elimination

Astrocytes

• Largest glial cells

• Perform multiple functions

Directions in the Vertebrate NS - BRAIN

• Anterior / Posterior ( Left / Right )

• Dorsal / Ventral ( Up / Down )

• Medial / Lateral ( In / Out )

Directions in the Vertebrate NS - Spinal Cord

• Anterior / Posterior ( Up / Down )

• Dorsal / Ventral ( Right / Left )

• Medial / Lateral ( In / Out )

Anatomy of the Spinal Cord

• Gray matter

  • Cell bodies and unmyelinated interneurons

• White matter

  • Myelinated axons

• 31 pairs of nerves

• Dorsal Roots

  • Sensory - Afferent

• Ventral Roots

  • Motor - Efferent

5 Major Divisions of the Brain

• Forebrain

  • Telencephalon

  • Diencephalon

• Midbrain

  • Mesencephalon

• Hindbrain

  • Metencephalon

  • Myelencephalon

Myelencephalon

• Medulla

• Reticular Formation

• Arousal system

Metencephalon

• 2 parts

  • Cerebellum

  • Pons

• RF

Mesencephalon

• Tectum

  • Superior colliculi ( visual motor )

  • Inferior colliculi ( auditory )

• Tegmentum

  • RF

  • Red nucleus (sensorimotor)

  • Substantia nigra (sensorimotor)

  • Periaqueductal gray (analgesic)

Diencephalon

Small Area in forebrain

• Thalamus

  • Sensory Relay Nuclei

• Hypothalamus

  • Below thalamus

  • Above PG

  • Endocrine function

  • Motivated behaviors

• Optic Chiasm

Telencephalon - Cerebral Hemispheres

Largest Divison

• Characterized by cortex

  • Many convolutions . folds

    • Fissures and Gyri

• Commisures connect TWO hemispheres

  • ie. corpus callosum

• Four Lobes

  • Frontal (Motor)

  • Parietal (Sensory)

  • Temporal (Auditory)

  • Occipital (Visual)

Subcortical Areas - Limbic System

• Regulates motivated behaviors

• Structures

  • Amygdala

  • Hippocampus

  • Mammillary body

  • Fornix

  • Septum

Subcortical Areas - Basal Ganglia

• Regulates movement

• Structures

  • Striatum ( Caudate & Putamen )

  • Nucleus Accumbens

  • Globus Pallidus

Pathway to substantia nigra to striatum deteriorates with Parkinson’s

Summary of Brain Structures