ANAT1101 Module 13: Nervous System

ANAT1101 Module 13: Nervous System

Neurons

It is the functional unit that sends impulses.

Neuroglia Cells

It protects and supports neurons.

Oligodendrocytes

A neuroglia cell in CNS that forms myelin sheath.

Ependymal Cells

A neuroglia cell in CNS that lines the spinal cord and cavities of the brain.

Microglia

A neuroglia cell in CNS that perform phagocytosis.

Astrocytes

A neuroglia cell in CNS that forms blood-brain barrier.

Astrocytes

It is the most numerous neuroglia cells found in the CNS.

Schwann Cell

A neuroglia cell in PNS that forms myelin sheath.

Astrocytes

It wraps around blood vessels that supply the brain, protecting brain from foreign substances.

Astrocytes

It allows the diffusion of small molecules but blocks large molecules and most medications.

Schwann Cells

It forms myelin sheath in PNS that can regenerate if damaged.

Oligodendrocytes

It forms myelin sheath in the CNS and cannot regenerate if damaged.

Neurons

It facilitates communication within and between CNS and PNS.

Nerves

These are neurons bundled together with connective tissue.

Sensory Nerve

Sensory neurons bundled together.

Motor Nerves

Motor neurons bundled together.

Mixed Nerve

Bundle of both sensory and motor neurons.

Interneuron Nerve

Bundle of interneurons.

Sensory Neurons

• Also called as Afferent neurons.

• It carries impulses toward the CNS.

Interneurons

• It is only located in CNS.

• It connects pathways and carry signals within CNS.

Motor Neuron

• Also called as Efferent neurons.

• It carry impulse from the CNS to muscles or glands/organs (effector).

Dendrites

Structure of a neuron that receives information from the environment or another neuron.

Cell Body

Structure of a neuron that processes the information.

Axon

Structure of neuron that sends information onwards (to another neuron or a muscle/gland/organ).

Myelin Sheath

It insulates the axon to speed up electrical impulses.

Nodes of Ranvier

These are the gaps in the myelin sheath.

Synaptic Knobs

These are the branched ends of the axon and where the neurotransmitters are released.

Action Potential

It is the movement of the ions within a neuron.

Synaptic Transmission

It is the process by which neurotransmitters are released from synaptic knobs and bind to receptors on the postsynaptic neuron, facilitating communication between neurons.

Multipolar Neurons

Type of neuron that has one axon and multiple dendrites.

Bipolar Neurons

Type of neuron with one axon and one dendrite.

Unipolar Neurons

Type of neuron that has a single process extending from the cell body before branching in a T shape.

Electrical Signaling

The process by which neurons communicate through the transmission of action potentials and neurotransmitter release.

Chemical Signaling

The process of communication between neurons through the release of neurotransmitters across synapses, allowing for the transmission of signals.

Polarized Cell

A type of cell that is negatively charged inside, and positively charged outside.

Sodium Ion

Ion that is inside the cell. It has a higher concentration outside the cell.

Potassium Ion

Ion that is outside the cell. It has a higher concentration inside the cell.

Sodium Potassium Pump

It pumps out 3 sodium ions outside for every 2 potassium ions inside the cell.

Sodium Potassium Pump

It is an example of active transport and requires energy to function.

Resting Potential

Conditions:

• Sodium ions are mostly outside the cell.

• Potassium ions are mostly inside the cell.

• The inside of the cell has a negative charge while outside has a positive charge.

  • It is because of the sodium-potassium pump.

Start of Depolarization

Conditions:

• Stimulus causes a few sodium channels to open.

• Sodium ions starts to move inside the cell.

• Potassium ions are still inside the cell.

• The inside of the cell starts to get positive charge.

Depolarization

Conditions:

• Sodium ions rushes inside the cell.

• Potassium ions are still inside the cell.

• Inside of the cell becomes more positive, outside more negative, progressing along the length of axon.

Repolarization

Conditions:

• Potassium channels open to restore charge, sodium channels closes.

• Sodium ions remains inside the cell.

• Potassium ions rushes outside the cell.

• Charge separation restored.

Refractory Phase

Conditions:

• Sodium potassium pump becomes active.

• Sodium ions are pumped outside the cell.

• Potassium ions are pumped inside the cell.

Myelination

The process by which a fatty sheath, called myelin, forms around the axons of neurons. It speeds up nerve impulses because action potentials only occur at the Nodes of Ranvier.

Spinal Cord

It is the information highway between brain and rest of the body.

Spinal Cord

It connects sensory and motor neurons to the CNS.

Spinal Cord

It is involved in the somatic reflexes.

Spinal Nerves

This is the nerve from PNS that branches out the spinal cord.

White Matter

The matter that contains the myelinated axons and spinal tracts.

Grey Matter

The matter in the spinal cord that is “H” shaped and contains unmyelinated neurons that are synapsing.

Grey Matter

The matter in the spinal cord where most of the sensory and motor neurons of the spinal nerves are synapsing with the interneurons of the spinal cord.

Ascending Tract

The spinal tract that send sensory signals up spinal cord to brain.

Descending Tract

It is the spinal tract that send motor impulses down the spinal cord.

Plexus

These are nerves that originate from the same area, and the branches serve specific body sites.

Cervical Plexus

Plexus in the neck, top of shoulders, and part of head.

Branchial Plexus

Plexus on the lower shoulder and arms

Lumbar Plexus

Plexus on the legs.

Sacral Plexus

Plexus at the back of legs.

Meninges

Three layers of connective tissues that protects the spinal cord.

Pia Matter

The layer of meninges that is transparent and clings to the spinal cord.

Arachnoid Matter

The layer of meninges that is delicate and web-like.

Dura Matter

The tough outer layer of the meninges.

White Matter

The matter in the brain that is myelinated and is where the impulses are carried between brain regions and to spinal cord.

Grey Matter

The matter in the brain that is unmyelinated and covers the surface of the brain.

Corpus Callosum

It is the bridge between brain and hemispheres.

Spinal Tracts

These are the bridges to the spinal cords and where the crossing over happens.

Left brain

It processes language and logic.

Right Brain

It processes creativity and spatial awareness.

Midbrain

It relays impulses between brain and spinal cord.

Pons

It relays impulses between brain and spinal cord, and some regulatory processes.

Medulla Oblongata

It controls involuntary responses like blood pressure, heart rate, and breathing (vitals).

Cerebellum

It is crucial for balance, coordination, and posture.

Thalamus

Part of diencephalon that relays and filters information from most of the senses.

Hypothalamus

Part of the diencephalon that controls the autonomic nervous system, pituitary gland, and homeostasis.

Frontal Lobe

It is involved in moving voluntary muscles, and decision making/judgements, memory, emotion, and personality.

Temporal Lobe

It is involved in auditory reception, understanding speech, and retrieving verbal memories.

Parietal Lobe

Receives and processes sensory information from skin and surrounding areas.

Occipital Lobe

It receives and analyzes visual information.

Primary Somatic Sensory Area

It is located in the parietal lobe and is responsible for processing sensory information from the body through the thalamus, such as touch, temperature, pain, and proprioception.

Primary Somatic Motor Area

It is located in the frontal lobe and sends impulses via motor tracts to skeletal muscles, and movement occurs.

Limbic System

The “emotional brain” and memory.

Hippocampus

It converts short-term memory into long-term memory.

Amygdala

It can store emotional memories and is involved in processing emotions such as anger, fear, jealousy, pleasure, and sexual feelings.

Ventricles

These are four interconnected chambers in the brain.

Cerebrospinal Fluid

It is produced by the blood vessels lining each ventricle.

Cerebrospinal Fluid

It is a clear, colourless fluid that fills the brain ventricles and the spinal cord.

Cerebrospinal Fluid

It is a fluid that protects (fluid shock absorber) the brain, provides extra oxygen and glucose, and removes waste.

Cranial Nerves

It is like the spinal nerves that consists of sensory and motor neurons but is synapse in the brain directly. It has 12 nerves.

Sensory Neuron

Cranial nerve has what type of neuron?

Sensory Neuron

Optic nerve has what type of neuron?

Motor Neuron

Oculuomotor nerve has what type of neuron?

Motor Neuron

Trochlear nerve has what type of neuron?

Both Neuron

Trigeminal nerve has what type of neuron?

Motor Neuron

Abducens nerve has what type of neuron?

Both Neuron

Facial nerve has what type of neuron?

Sensory Neuron

Vestibulocochlear nerve has what type of neuron?

Both Neuron

Glossopharyngeal nerve has what type of neuron?

Both Neuron

Vagus nerve has what type of neuron?

Motor Neuron

Accessory (spinal) nerve has what type of neuron?