Lecture 2 - Organization and the Nervous System

Flashcards covering the hierarchy of biological organization and the anatomical and functional divisions of the human nervous system based on the lecture material.

Chemical level

The level of organization where atoms combine to form molecules.

Cellular level

The level where cells are made up of molecules.

Tissue level

The level where tissues consist of similar types of cells.

Organ level

The level where organs are made up of different types of tissues.

Organ system level

The level where organ systems consist of different organs that work together closely.

Organismal level

The level where the human organism is made up of many organ systems.

Cytology

The microscopic anatomy of cells.

Histology

The microscopic anatomy of tissues.

Sensory input

Information gathered by sensory receptors about internal and external changes.

Integration

The interpretation of sensory input within the nervous system.

Motor output

The activation of effector organs (muscles and glands) to produce a response.

Central nervous system (CNS)

Consists of the spinal cord and brain; functions to process and coordinate sensory data, motor commands, and higher brain functions such as intelligence and memory.

Peripheral nervous system (PNS)

Includes all neural tissue outside the CNS; delivers sensory information to the CNS and carries motor commands to peripheral tissues.

Cranial nerves

Bundles of axons in the PNS that connect to the brain.

Spinal nerves

Bundles of axons in the PNS that attach to the spinal cord.

Afferent division

The functional division of the PNS that carries sensory information from sensory receptors to the CNS.

Efferent division

The functional division of the PNS that carries motor commands from the CNS to muscles and glands.

Receptors

Neurons, specialized cells, or complex sensory organs (e.g., eyes, ears) that detect changes or respond to stimuli.

Effectors

Cells and organs that respond to efferent signals.

Somatic nervous system (SNS)

A division of the efferent PNS that controls voluntary and involuntary (reflex) skeletal muscle contractions.

Autonomic nervous system (ANS)

A division of the efferent PNS that controls subconscious actions, such as contractions of smooth and cardiac muscle and glandular secretions.

Sympathetic division

The division of the ANS that has a stimulating effect.

Parasympathetic division

The division of the ANS that has a relaxing effect.

Preganglionic neuron

A neuron in the CNS with a thin, lightly myelinated axon that is part of the two-neuron chain in the ANS.

Ganglionic neuron

A neuron in an autonomic ganglion with an unmyelinated postganglionic axon that extends to an effector organ.

Acetylcholine (ACh)

The neurotransmitter released by all somatic motor neurons and all preganglionic fibers of the ANS.

Norepinephrine (NE)

A neurotransmitter released by most sympathetic postganglionic fibers at the effector organs.