Nervous System and Chemical Synapses

Comprehensive vocabulary flashcards covering chemical synapses, specific neurotransmitters, the divisions of the nervous system, and the anatomical structures/functions of the brain.

Chemical synapses

Biological junctions through which neurons' signals are exchanged to each other or to non-neuronal cells such as muscles or glands using a neurotransmitter.

$Ca^{++}$ (Calcium ions)

Ions that enter the axon terminal through channels opened by an impulse, initiating the release of neurotransmitters from vesicles.

Synaptic cleft

The gap across which a neurotransmitter travels after being released from a vesicle to reach the protein receptor on a dendrite.

Excitatory postsynaptic potential (EPSP)

A depolarization of the postsynaptic membrane caused by the entry of $Na^{+}$ ions, making the neuron more likely to fire an action potential.

Acetylcholine (Ach)

A common neurotransmitter that is excitatory to skeletal muscles and can be excitatory or inhibitory at other locations; secreted in the CNS and PNS.

Norepinephrine

A neurotransmitter involved in wakefulness and the fight-or-flight response, secreted in the CNS and PNS from postganglionic sympathetic neurons.

Dopamine

A neurotransmitter generally classified as excitatory that relates to voluntary movement and emotions.

Serotonin

A neurotransmitter generally classified as inhibitory that is secreted in the CNS and is involved in sleep.

GABA (gamma-aminobutyric acid)

An inhibitory neurotransmitter in the Central Nervous System associated with motor behaviour.

Cholinesterase

An enzyme responsible for the enzymatic degradation or breakdown of acetylcholine in the synapse.

Prozac

A specific medication defined as a serotonin reuptake inhibitor.

Summation

The accumulation of neurotransmitters from two or more neurons, including spatial and temporal types, which determines if the threshold voltage is reached for an action potential.

Somatic nerves

A part of the PNS consisting of a single motor neuron leading from the CNS to effectors like skeletal muscles, regulated by conscious control.

Autonomic nerves

A part of the PNS regulating effectors without conscious control, such as cardiac muscle and glands, using a set of two motor neurons synapsing in a ganglion.

Central Nervous System (CNS)

The body's processing center, made up of the brain and the spinal cord.

Peripheral Nervous System (PNS)

The part of the nervous system consisting of nerves that connect the brain and spinal cord to the rest of the body.

Meninges

A series of three membranes that surround and protect the central nervous system.

Ventricles

Cavities within the brain that produce and store cerebrospinal fluid.

Astrocytes

Nerve cells associated with the blood-brain barrier.

Corpus callosum

A series of nerve fibres that connect the left and right hemispheres of the brain.

Cerebellum

Known as the 'little brain,' it coordinates posture, reflexes, body movements, and fine voluntary motor skills.

Medulla oblongata

Located at the base of the brainstem, it contains centres to control autonomic functions like heart rate, blood pressure, and breathing.

Pons

A relay centre between the right and left halves of the cerebrum, the cerebellum, and the rest of the brain.

Midbrain

A brain region that relays visual and auditory information and plays a role in eye movement and skeletal muscle control.

Thalamus

Often called 'the great relay station of the brain,' it connects various parts of the brain, particularly sensory systems and the cerebellum.

Hypothalamus

A region that regulates the internal environment, drives like hunger and thirst, and coordinates the actions of the pituitary gland.

Cerebrum

The largest part of the brain, divided into hemispheres, containing centres for intellect, memory, consciousness, and language.

Proprioceptors

Specialized sensors located within skeletal muscles and joints that send information to the cerebellum.

Frontal lobe

The portion of the brain that regulates conduct, personality, and verbal communication.

Parietal lobe

The portion of the brain that processes information about the body's position, orientation, and touch sensitivity.

Occipital lobe

The pair of lobes in the cerebral cortex primarily associated with visual processing.

Temporal lobe

The pair of lobes in the cerebral cortex primarily associated with auditory processing.