A+P Week 5 - Neural System

What is the anatomical organisation of the nervous system?

Division into the central nervous system (CNS) and peripheral nervous system (PNS).

What structures make up the CNS?

Brain and spinal cord.

What structures make up the PNS?

Cranial nerves, spinal nerves, and ganglia.

What is the functional organisation of the nervous system?

Division into sensory (afferent) and motor (efferent) systems.

What is the role of the sensory nervous system?

Carries information from receptors to the CNS.

What is the role of the motor nervous system?

Carries commands from the CNS to effectors.

What are the parts of a typical neuron?

Dendrites, cell body, axon, myelin sheath, nodes of Ranvier, and axon terminals.

What is the function of dendrites?

Receive incoming signals.

What is the function of the axon?

Conduct action potentials away from the cell body.

What is the myelin sheath?

A lipid-rich insulating layer around axons.

What is the function of the myelin sheath?

Increases speed of nerve impulse conduction.

What are nodes of Ranvier?

Gaps in the myelin sheath where ion exchange occurs.

How is resting membrane potential created?

Unequal distribution of ions across the membrane.

What is the typical resting membrane potential of a neuron?

Approximately -70 mV.

What maintains resting membrane potential?

Sodium-potassium pumps and selective membrane permeability.

What is the function of the sodium-potassium pump?

Moves 3 Na+ out and 2 K+ into the cell using ATP.

What is an action potential?

A rapid reversal of membrane potential that travels along the axon.

What triggers an action potential?

Depolarisation reaching threshold.

What happens during depolarisation?

Sodium channels open and Na+ enters the neuron.

What happens during repolarisation?

Potassium channels open and K+ leaves the neuron.

What happens during hyperpolarisation?

Membrane potential briefly becomes more negative than resting potential.

How does an action potential propagate?

Depolarisation in one segment triggers depolarisation in the next.

What is saltatory conduction?

Action potentials jumping between nodes of Ranvier in myelinated axons.

What is a synapse?

A junction between neurons or between a neuron and an effector.

What are the main parts of a synapse?

Presynaptic terminal, synaptic cleft, and postsynaptic membrane.

What is a chemical synapse?

A synapse using neurotransmitters for communication.

What is an electrical synapse?

A synapse where ions pass directly through gap junctions.

What is the main difference between chemical and electrical synapses?

Chemical synapses use neurotransmitters; electrical synapses allow direct ion flow.

What is grey matter?

Nervous tissue containing neuron cell bodies and dendrites.

What is the function of grey matter?

Information processing and integration.

What is white matter?

Nervous tissue containing myelinated axons.

What is the function of white matter?

Transmission of nerve impulses.

What are the six major regions of the brain?

Cerebrum, diencephalon, midbrain, pons, medulla oblongata, and cerebellum.

What is the function of the cerebrum?

Conscious thought, sensation, memory, and voluntary movement.

What is the function of the diencephalon?

Sensory relay and homeostasis regulation.

What is the function of the midbrain?

Visual and auditory reflexes.

What is the function of the pons?

Relay between brain regions and breathing regulation.

What is the function of the medulla oblongata?

Controls vital autonomic functions like heart rate and breathing.

What is the function of the cerebellum?

Coordination, balance, and motor control.

What structures make up the limbic system?

Hippocampus, amygdala, hypothalamus, and cingulate gyrus.

What is the function of the hippocampus?

Memory formation.

What is the function of the amygdala?

Emotional processing.

What is the function of the hypothalamus?

Homeostasis and autonomic/endocrine regulation.

What are the main regions of the cerebrum?

Frontal, parietal, temporal, and occipital lobes.

What is the function of the frontal lobe?

Motor control, planning, reasoning, and speech.

What is the function of the parietal lobe?

Somatic sensory processing.

What is the function of the temporal lobe?

Hearing, memory, and language.

What is the function of the occipital lobe?

Vision processing.

What is the primary motor cortex?

Region controlling voluntary skeletal muscle movement.

What is the primary somatosensory cortex?

Region receiving sensory input from the body.

What is the visual cortex?

Region processing visual information.

What is the auditory cortex?

Region processing sound.

What are association areas?

Brain regions integrating and interpreting information.

What are the components of the spinal cord?

Grey matter, white matter, central canal, dorsal roots, and ventral roots.

What is a reflex arc?

A rapid automatic response pathway.

What are the components of a reflex arc?

Receptor, sensory neuron, integration centre, motor neuron, and effector.

What is an example of a reflex response?

Withdrawal reflex or knee-jerk reflex.

What are sensory receptors?

Structures that detect changes in the environment.

How do sensory receptors respond to specific stimuli?

Each receptor is specialised for a particular type of stimulus.

How does receptor organisation affect sensitivity?

Receptors with smaller receptive fields provide greater sensitivity and precision.

What are general senses?

Sensations distributed throughout the body such as touch, pain, temperature, and proprioception.

What receptors detect touch and pressure?

Mechanoreceptors.

What receptors detect temperature?

Thermoreceptors.

What receptors detect pain?

Nociceptors.

What receptors detect body position?

Proprioceptors.

What is the somatic nervous system?

Division controlling voluntary skeletal muscle movement and conscious sensation.

What levels of information processing are involved in motor control?

Conscious, subconscious, and reflexive levels.

What is the autonomic nervous system (ANS)?

Division controlling involuntary functions of smooth muscle, cardiac muscle, and glands.

What is the difference between the somatic and autonomic nervous systems?

Somatic controls voluntary skeletal muscle; autonomic controls involuntary visceral functions.

What are the divisions of the autonomic nervous system?

Sympathetic and parasympathetic divisions.

What is the function of the sympathetic division?

Prepares the body for stress (“fight or flight”).

What is the function of the parasympathetic division?

Promotes rest, digestion, and energy conservation (“rest and digest”).

What are the effects of sympathetic stimulation?

Increased heart rate, dilated pupils, and reduced digestion.

What are the effects of parasympathetic stimulation?

Decreased heart rate and increased digestion.

What is dual innervation?

Most organs receive both sympathetic and parasympathetic nerve supply.

Why is dual innervation important?

Allows balanced regulation of organ activity.