Chapter 3

    Cards (81)

    • Of which 2 types of nerve cells does brain tissue consist of?
      Neurons -> information processing
      Glial cells -> support cells
    • How can we count nerve cells?
      brain soup
    • Cerebral cortex
      • 82% brain mass
      • ~ 16 billion neurons (19% brain neurons)!
      • ~ 61 billion glial cells
    • Cerebellum
      • 10% brain mass
      • ~ 69 billion neurons (80% brain neurons)
      • ~ 16 billion glial cells
    • Rest of brain (without cerebral cortex & cerebellum)
      • 8% brain mass
      • ~ 1 billion neurons (1% brain neurons)
      • ~ 8 billion glial cells
    • What are the 3 parts of neurons (basic structure)?
      dendrites -> no. many -> collect information (input) from other neurons
      cell body (soma) -> no. 1 -> integrates information
      axon -> no. 1 -> sends information (output) branches at the end
    • Neuron - basic structure
      first: Dendrites
      middle: cell body
      last: axon
    • Neurons -flow of information
      1. input (Dendrites)
      2. Integration (cell body)
      3. Output (Axon)
    • What are 3 major types of neurons?
      1. sensory neurons (Input; Afferent)
      2. interneurons (Association)
      3. motor neurons (Output; Efferent)
    • Sensory neurons
      = input (Afferent); bring info to the CNS
      • long Dendrites
      • short Axons
      • dendrites + cell body outside of CNS (cell body in dorsal root ganglion)
      • axon inside CNS
    • Interneurons
      = association; associate sensory & motor activity in CNS
      • short dendrites
      • short axons
      • dendrites, cell body & axon inside CNS (in brain + spinal cord)
    • Motor neurons
      = output (efferent); send signals from brain & spinal cord to muscles
      • short dendrites
      • long axons
      • dendrites + cell body inside CNS (in lower brainstem + spinal cord)
      • axon outside CNS
    • Dorsal root location
    • Sympathetic division (stimulation)
      1. Cranial 2. Cervical 3. Thoracic 4. Lumbar 5. Sacral
    • Glial cells
      = support cells
      What do they do?
      Aid neurons in processing information by providing:
      • physical support, protection
      • nutrients
      • increase conduction (lit. glue neurons together)
      • !!! DO NOT transmit info by themselves
    • Glial cell - image
    • What are the 5 major types of glial cells?
      Astrocytes, oligodendroglia, microglia, ependymal cells, Schwann cells
    • What are the features & functions of glial cell: Ependymal cell?
      • small, ovoid
      • secretes cerebrospinal fluid (CSF)
      • Appearance:
    • What are the features and function of the glial cell: Astrocyte?
      • star-shaped, symmetrical
      • nutritive & support function
      • Appearance:
    • What are the features and function of the glial cell: Microglial cell?
      • small, mesodermally derived
      • defensive function
      • appearance:
    • What are the features & function of the glial cell: Oligodendroglial cell?
      • asymetrical
      • forms myelin aroung axons in brain & spinal cord
      • appearance:
    • What are the features & function of the glial cell: Schwann cell?
      • asymetrical
      • wraps around peripheral nerves to form myelin
      • appearance:
    • Types of glial cells- table overview
    • Glial cells-– Ependymal cells (CSF)
      What is the normal brain & ventricles and what is the Hydrocephalus brain?
      red: normal brain & ventricles
      orange: ventricles
      yellow: Hydrocephalus brain
      green: swollen ventricles
    • What do the glial cells Astrocytes do?
      • structural support to the CNS (scaffold cells)
      • Move nutrients & chemicals between blood vessels & neurons
      • Enhance brain activity by contributing to increased blood flow
      • Stimulate repair of damaged brain tissue (scarring)
      • enable tight bond between blood-vessel cells & neurons -> blood-brain barrier
    • Astrocyte-glial cell image:
      1. Astrocyte 2. blood vessel 3. blood-vessel cells 4. astrocyte end feet 5. tight junctions 6. myelinated axon 7. Neuron
    • Glial cells – Microglia
      • only glial cell originating in blood as offshoot of immune system (type of macrophage) & migrate throughout nervous system (all other glial cells originate in the brain)
      • Identify & attack foreign tissue (defense cells)
      • Invade areas with damaged cells + provide growth factors to aid in repair
      • Consume dead & inflamed brain cells (plaques, Alzheimer)
    • What do Glial cells – Oligodendroglia and Schwann cells do?
      Myelinate neurons to enhance neural transmission speed (insulate axons)
      • Oligodendroglia (inside CNS)
      • Schwann cells (outside CNS)
    • Glial cells - Oligodendroglia (inside CNS)- image
      1. Oligodendrocytes 2. Dendrite 3. Neuron 4. Myelin sheath 5. Axon 6. Synapse 7. Nucleus
    • Glial cell - Schwann cells (outside CNS)- image
      1. Node of Ranvier 2. Nucleus 3. Schwann cells
    • Glial cells- Neuron repair
      Which glial cell encourages neuronal repair?
      Schwann cells (PNS) -> cells in the PNS can be repaired after damage
    • Glial cells- Neuron repair
      Which glial cells DO NOT encourage neuronal repair?
      Oligodendrocytes (CNS) -> cells in the CNS cannot be repaired (yet)
    • Glial cells – Neuron Repair
      How does it work/ look like?
      image:
    • Histology of Glial cells- How do we know all this information?

      traditional staining
      now: imaging techniques in living tissue (in vivo) -> DTI: Diffusion Tensor Imaging
      traditional staining- image:
    • What are the main disadvantages of staining?
      only works in fixed brain tissue (ex vivo, in vitro, post-mortem)
    • What is the internal structure of a typical (nerve) cell?
      cell membrane, Nucleus, Nuclear membrane, Endoplasmic reticulum, Golgi bodies, Microtubules, (also 3 others but not part of exam so left out)
    • What is the cell membrane?
      membrane surrounding the cell
    • What is the nucleus?
      cell core, contains chromosomes and genes
    • What is the nuclear membrane?
      surrounds nucleus
    • What does the Endoplasmic reticulum do?
      assembles proteins