Bio Lab II Nervous System

Nervous system

a complex biological network of nerves and neurons that transmits signals between the brain, spinal cord, and body; acts as the body’s primary control, regulation, and communication system, coordinating both voluntary movements and involuntary processes by detecting environmental stimuli

Central Nervous System (CNS)

the primary command center of the body, comprising the brain and spinal cord; processes information, controls cognitive functions, and coordinates bodily movements

Peripheral Nervous System (PNS)

consists of all neural structures—nerves, ganglia, and sensory receptors—located outside the brain and spinal cord; primary function is to serve as a communication network, connecting the CNS to the rest of the body's limbs, organs, and skin

The brains 3 major areas

1. Cerebrum (telencephalon, diencephalon)

2. Cerebellum

3. Brainstem (midbrain, pons, medulla oblongata)

Cerebrum

the largest and uppermost part of the brain, acting as the primary center for higher-order thinking, conscious thought, sensory processing, and voluntary muscle control; composed of telencephalon (cerebral cortex) and diencephalon

4 cerebral cortex lobes

1. Parietal

2. Frontal

3. Temporal

4. Occipital

Cerebellum

a major structure of the hindbrain located at the back of the skull, beneath the occipital/temporal lobes and behind the brainstem; responsible for coordinating voluntary movements, maintaining balance, posture, and facilitating motor learning

2 Diencephalon parts

1. thalamus

2. hypothalamus

Thalamus

paired, egg-shaped structure of grey matter located in the center of the brain, acting as the main relay station for sensory and motor signals traveling to the cerebral cortex

Hypothalamus

a small, vital structure at the base of the brain, located below the thalamus and above the brainstem, that serves as the primary link between the nervous and endocrine systems

Brainstem

the posterior, stalk-like part of the brain connecting the cerebrum to the spinal cord, controlling autonomic, involuntary life-sustaining functions such as breathing, heart rate, blood pressure, and sleep cycles.

Midbrain

the uppermost, smallest portion of the brainstem that connects the forebrain to the hindbrain; relay station for sensory input and motor output

Pons

critical component of the brainstem, positioned between the midbrain and medulla oblongata, that acts as a neural bridge connecting the forebrain, cerebellum, and spinal cord; serves as a passageway for nerve impulses running between the medulla and higher brain regions

Medulla oblongata

the lowest part of the brainstem, located between the pons and the spinal cord, responsible for regulating vital autonomic functions; controls internal organs

Spinal cord

a long, thin, tubular bundle of nervous tissue and support cells that extends from the brainstem down the center of the back, acting as the main pathway for information connecting the brain and the peripheral nervous system

Gray matter

a major component of the central nervous system (brain and spinal cord) comprised primarily of neuronal cell bodies, dendrites, unmyelinated axons, glial cells, and synapses

White matter

a component of the central nervous system —comprising the brain and spinal cord—that consists mainly of bundles of myelinated nerve fibers

3 neuron types

1. sensory neuron

2. interneuron

3. motor neuron

Sensory neuron

impulses from sensory receptor to spinal cord

Interneuron

transmits nerve impulses from sensory to motor neuron

Motor neuron

impulses from spinal cord to effector (muscle)

Eye

a specialized sensory organ that detects light and converts it into electrical impulses, enabling vision

Sclera

Outer layer of eye; protects and supports eyeball

Cornea

transparent portion of sclera; refracts light rays

Choroid

middle layer of eye; absorbs stray light rays

Retina

inner layer of eye; contains receptors for sight

Rod cells

in retina; black and white vision

Cone cells

concentrated in fovea centralis; color vision

Fovea centralis

special region of retina; makes acute vision possible

Lens

interior of eye between cavities; refracts and focuses light rays

Ciliary body

extension behind choroid; holds lens/accommodation

Iris

more anterior extension of choroid; regulates light entrance

Pupil

opening in middle of iris; admits light

Humors (aqueous and vitreous)

fluid media (anterior and posterior); transmits/refracts light rays

Optic nerve

Extends from posterior of eye; transmits impulses to brain

Ear

the specialized vertebrate organ responsible for detecting sound (hearing) and maintaining body balance (equilibrium)

Pinna

collects sound waves

Auditory canal

filters air

Tympanic membrane and ossicles

amplify sound waves

Auditory tube

equalizes air pressure

Semicircular canals

rotational equilibrium (stereocilia/cupula)

Vestibule (utricle and saccule)

gravitational equilibrium (stereocilia/otolithic membrane)

Cochlea (spinal organ)

hearing (stereocilia/tectorial membrane)