Nervous System and Brain Structures

Flashcards about the nervous system, neurons, and brain structures.

Neuron

Functional unit of the nervous system; specialized cell that sends nerve impulses.

Dendrites

Branches around the cell body that receive signals and send them down the neuron.

Axon

The tail of the neuron where signals travel.

Axon Hillock

Part of the axon that joins the cell body.

Axon Terminal

End of the axon where a neuron connects with another neuron's dendrites.

Myelin Sheath

Thick, insulated layers of the axon that speed up signal travel; produced by Schwann cells.

Nodes of Ranvier

Uninsulated gaps between Myelin Sheaths that allow electrical signals to skip and travel quickly.

Afferent (Sensory) Neurons

Transmit signals from sensory organs to interneurons.

Interneurons (Associative Neurons)

Interpret signals and create a response; found in the brain and spinal cord.

Efferent (Motor) Neurons

Carry signals from interneurons to the effector (muscle or gland).

Synapse

Gap between one neuron and another where signals must cross.

Presynaptic Neuron

Neuron sending the signal.

Postsynaptic Neuron

Neuron receiving the signal.

Central Nervous System

Consists of interneurons (brain and spine).

Peripheral Nervous System

Afferent and Efferent Neurons that connect to the Central Nervous System.

Somatic System

Efferent neurons found mostly in the musculoskeletal system; voluntary (under your control).

Autonomic System

Efferent neurons that control smooth muscles and glands; not voluntary.

Sympathetic System

System that prepares the body for action; consumes energy; fight or flight.

Parasympathetic System

System that promotes relaxation and calm; conserves energy.

Neurotransmitters

Molecules produced by the Axon Terminal of Neurons that transmit signals across the synaptic cleft.

Synaptic Cleft

A space between the axon terminal and the receiving dendrites.

Meninges

Protective layers of connective tissue surrounding the spinal cord and brain.

Cerebrum

The largest and most developed region of the brain that controls motor activities, language, learning, and memory.

Hypothalamus

Brain area that regulates basic homeostatic mechanisms such as body temperature, hunger, and osmotic balance.

Pituitary Gland

Gland of the endocrine system involved in regulating physiological processes such as stress, growth, reproduction, and lactation.

Pons ('bridge')

Mass of fibers that transfers nerve signals between the cerebellum and the medulla.

Medulla oblongata (Medulla)

Connects the spinal cord to the cerebellum and is important in autonomic nerve control.

Cerebellum

Brain area involved in somatic (voluntary) nerve control (muscle movement).