BIO 1720 Lecture 3: The Nervous System

Central Nervous System (CNS)

Composed of the brain and spinal cord; responsible for processing and integrating information.

Peripheral Nervous System (PNS)

Connects the CNS to the rest of the body; includes sensory and motor neurons;

Transmits signals from the brain

Transmits sensory signals to the brain

Sensory-somatic Nervous System (PNS)

Transmits sensory information from skin, muscles and sensory organs to the CNS

Motor System (PNS)

Send motor commands from the CNS to the skeletal muscles

Autonomic Nervous System (PNS)

Controls bodily functions without conscious control

- Sympathetic Nervous System

- Parasympathetic Nervous Systems

- Enteric Nervous System

The autonomic nervous system controls

lungs, heart, smooth muscle, and exocrine & endocrine system

Enteric System (autonomic)

control over digestive tracts, gall bladder, pancreas

sympathetic nervous system

Arousal and energy generation. Controls fight or flight response. Prepares body for physical strain of escaping (running) or danger (fending off a predator)

parasympathetic nervous system

Calming and return to normalcy. Connection between the CNS and internal organs.

Ganglia

Clusters of neuron cell bodies in the PNS; act as mini processing centers.

Nerve Cord

Bundled axons that transmit signals; part of both simple and complex nervous systems

Decentralized Nerve Net

A simple nervous system found in organisms like cnidarians; lacks a central brain.

periosteum

fiberous tissue covering bone

dura mater

“Hard mother” thick layer to protect brain spinal cord also well vascularized

arachnoid

Spiderweb like covering of Brain and spinal cord

pia mater

‘Soft mother” that overlayers the brain and spinal cord like plastic wrap

Chronic Traumatic Encephalopothy (CTE)

tangles of a protein build up in the brain after repeated head impacts – resembles Alzheimer’s.

Cerebrum

Largest brain region (upper part of Brain); Frontal Lobe, Somatosensory, Parietal Lobe, Occipital Lobe, Temporal Lobe, Motor Cortex

corpus callosum

Thick band of nerve fibers connecting the left and right cerebral hemispheres

gyri

raised folds/hills on brain surface; increase surafce area

sulci

grooves/ valleys on brain surface; increase surface area

cerebellum

coordinates movement, balance, and motor skills

Diencephalon

Thalamus, hypothallus, pituitary gland

Hormone function

brainstem is made up of

pons, medulla

responsible for breathing, heart rate, BP

hypothalamus

Controls much of endocrine system via pituitary gland; regulates body temperature and circadian rhythms

pituitary gland

produce and release hormones.

thermostat, biological clock

Cerebral Cortex

Outer layer of the cerebrum; involved in perception, learning, emotion, and voluntary movement, sensation

thalamus

Regulates consciousness, arousal, sleep. Sorts information from senses and cerebrum and sends it to cerebral areas for processing

cerebellum

Coordinates movement and balance, motor skills

medulla

Heartbeat, respiration, digestion, swallowing, vomiting

pons

Bridge connecting PNS to Cerebrum

Frontal lobe

Involved in planning, decision-making, speech, and olfactory processing, cognitive function

somatosensory lobe

Touch, Pressure, heat, cold, orientation in space

parietal lobe

Speech and reading. Integration of sensory information

occipital lobe

Seeing, recognizing, identifying. Processing visual information

temporal lobe

Processing, interpreting sound

motor cortex

controls voluntary muscle movements

Somatosensory and motor cortex

The cortical surface area devoted to each body part as represented by a proportional body part size

Greater surface area = finer motor skills and greater sensation

homunculus

Shows relative weighting given to different parts of the body relative to on motor and sensory cortex surface area devoted to each body part

cranial nerves

12 pairs of nerves originating from the brain; control sensory and motor functions in the head and neck.

vagus nerve

Regulates internal organ functions including digestion, heart rate, and reflexes like coughing and swallowing

spinal cord nerves

Transmit sensory and motor information between the spinal column and the rest of the body

refelx arc

A neural pathway that controls a reflex action; involves sensory and motor neurons.

2 cells that the nervous system is made up of

neurons and glial cells

neurons

Transmit electrical and chemical signals – electrical wire

glia cells

Support functions/information processing – workers at the

electric company

parts of a neuron

soma, axon, dendrite, node of ranvier, synapse, axon terminal, oligodendrocyte