nervous system

What does CNS stand for?

Central Nervous System

What organs are included in the CNS?

Brain and spinal cord

What makes up the Peripheral Nervous System (PNS)?

All nerves outside the brain and spinal cord

What is a neuron?

A nerve cell that transmits signals

What is a nerve?

A bundle of neuron fibers

What is the difference between sensory and motor neurons?

Sensory neurons carry signals to the CNS; motor neurons carry signals away from the CNS

What does afferent mean?

Carrying signals toward the CNS

What does efferent mean?

Carrying signals away from the CNS

What is an effector?

A body part that responds to nerve signals

Name two effectors.

Muscles and glands

What does the somatic nervous system control?

Voluntary movements

What does the autonomic nervous system control?

Involuntary functions like heartbeat and digestion

What two muscle types are controlled by the autonomic nervous system?

Smooth muscle and cardiac muscle

What is the role of the sympathetic nervous system?

Fight-or-flight response

Name three effects of sympathetic activation.

Increased heart rate, dilated pupils, faster breathing

What is the role of the parasympathetic nervous system?

Rest-and-digest functions

What do dendrites do?

Receive signals

What is the function of the axon?

Carries impulses away from the cell body

What is the soma?

The neuron cell body containing the nucleus

What is myelin?

Insulating covering around axons

What is the function of myelin?

Speeds up nerve signal transmission

What are Nodes of Ranvier?

Gaps in the myelin sheath

What problems can occur with myelin deficiency?

Slow nerve signals, weakness, poor coordination

What is a stimulus?

A change that triggers a response

What is threshold?

Minimum stimulus needed to activate a neuron

What is a response?

Reaction to a stimulus

What does serotonin do?

Regulates mood and sleep

What does acetylcholine do?

Helps muscle contraction and memory

What does epinephrine do?

Increases alertness and heart rate

What are the three layers of the eye?

Fibrous, vascular, and neural layers

What structures are in the fibrous layer?

Cornea and sclera

What structures are in the vascular layer?

Choroid, iris, ciliary body

What structure is in the neural layer?

Retina

What does the retina do?

Detects light

What does the optic nerve do?

Carries visual signals to the brain

What is the cerebrum responsible for?

Thinking, memory, voluntary actions

What does the cerebellum control?

Balance and coordination

What does the brainstem control?

Basic life functions like breathing and heartbeat

What are gyri?

Raised folds in the brain

What are sulci?

Grooves between gyri

What is the corpus callosum?

Connects the two brain hemispheres

What are neurotransmitters?

Chemicals that transmit signals between neurons

About how many neurotransmitters are known?

Over 100

What are general left brain functions?

Logic, math, language

What are general right brain functions?

Creativity and spatial awareness

What are meninges?

Protective membranes around the brain and spinal cord

What is the dura mater?

Tough outer meningeal layer

What is the arachnoid mater?

Web-like middle layer

What is the pia mater?

Thin inner layer attached to the brain

What are dermatomes?

Skin regions supplied by spinal nerves

What do rods detect?

Dim light and black-and-white vision

What do cones detect?

Color and fine detail

What is a synapse?

Gap between neurons where signals pass

Why are more males colorblind?

Colorblindness is usually linked to the X chromosome, and males only have one X chromosome.