Nervous System Flashcards
Functions
Sensory input Integration Homeostasis Mental activity Control of muscles and glands
Sensory input - function
Sensory receptors monster numerous external and internal stimuli
Integration - function
Brain and spinal cord are major organs for processing sensory input and initiating responses
Homeostasis - function
Nervous system regulates, coordinates and activates in order to maintain homeostasis
Mental activity - function
Brian is the centre of mental activities, including consciousness, thinking ect
Control of muscles and glands - functions
Nervous system controls the major movements of the body through the control of skeletal muscle
Peripheral nervous system
Cranial nerves
Spinal nerves
Ganglia
Ganglia
Neuron cell body collections outside CNS
The brain is protected by
skull, the meninges and cerebrospinal fluid
4 divisions of the brain
Cerebrum
Cerebellum
Diencephalon
Brainstem
Spinal cord functions
Acts as a conduit for impulse conduction to and from the brain
Integrates incoming information and produces response through reflex mechanisms
Spinal cord reflexes
No input from the brain
Stretch reflex
Golgi tendon reflex
Withdrawal reflex
Peripheral nervous system subcategories
Sensory (afferent) division
Motor (efferent) division
Sensory (afferent) division
Transmit electrical signals (action potentials) from sensory receptors to CNS
Motor (efferent) division
Transmit action potentials from CNS to effector organs
Divided into the somatic NS and autonomic NS
Somatic system - transmit action potentials from CNS to skeletal muscle
ANS - transmits action potentials from the CNS to smooth and cardiac muscle and certain glands
ANS - subdivided into sympathetic and parasympathetic divisions
Autonomic nervous system
Parasympathetic
Sympathetic
Parasympathetic
Conservation of energy (rest and digest, feed and breed)
Selective regulation of visceral effectors
Visceral effects (slow HR)
Sympathetic
Mobilisation of energy
Total activation of visceral effects
Visceral effects
Cells of nervous system
Neurons
Supporting cells
Neurons (nerve cells)
Basic structural and functional unit of the nervous system
Capable of generating and conducting an action potential
Communicate with other cells by means of a chemical or electrical synapse
Supporting cells
Support, insulate and maintain neurons
Neuroglia in CNS
Schwann cells and satellite cells in PNS
Neuron structure
Cell body
Axon
Dendrites
Cell body
Houses the control centre
Contains a single relatively large nucleus
Axon
A single axon conducts action potentials away from the neutron cell body
End of axon terminals which communicate with other cells by means of a chemical or electrical synapse
A nerve is a bundle of axons
Dendrites
Conduct action potentials towards the neutron cell body
Types of neurons
Multipolar
Bipolar
Unipolar
Multipolar neurones
Many dendrites and single axon
Most of neurons within CNS and motor neurons
Bipolar Neurons
One dendrite and 1 axon from cell body
Specialised cells
Located in some sensory organs
Unipolar neurones
One process emerges from cell body
Most sensory neurons
Single process extending from body
Sensory receptors
Chemoreceptors Photoreceptors Thermoreceptors Mechanoreceptors Nocireceptors
Chemoreceptors
Generate action potential in repose to specific chemical stimuli
Photoreceptors
Generate action potentials in response to visible light
Thermoreceptors
Generate action potentials in response to temperature
Mechanoreceptors
Generate action potentials in response to physical force
Nocireceptors
Generate action potentials in response to tissue/cell damage
Reflex arc components
Sensory receptor Afferent/sensory neuron Association/inter neuron Efferent/motor neuron Effector organ
Spinal cord reflexes
Stretch
Golgi tendon reflex
Withdrawal reflex
Stretch reflex
Simplest
Maintains posture
Knee-jerk reflex
Golgi tendon reflex
Prevents excessive pressure to tendons
Reflex not always adequate for athletes
Weight lifters suddenly dropping heavy weight
Withdrawal reflex
Remove limb from pain
