Unit 3.3 - Nervous & Endocrine Systems

Nervous System

the body’s communication network consisting of a complex system of nerves, neurons, and specialized cells

Central Nervous System (CNS)

Brain and spinal cord - it serves as the command center of the body responsible for processing information, coordinating responses, and regulating bodily functions

Peripheral Nervous System (PNS)

consists of all the nerves outside the brain and spinal cord (communication network, sensory info. to the CNS)

Autonomic Nervous System 

regulates involuntary bodily functions (automatic) 

• consists of sympathetic and parasympathetic nervous system 

Sympathetic Nervous System

responsible for activating the body’s fight or flight response in times of stress or danger 

Parasympathetic Nervous System

promoting relaxation and restoring the body to a calm state after experiencing stress or danger

Somatic Nervous System

division of peripheral nervous system responsible for controlling voluntary movements and relaying sensory information 

Neurons

specialized cell that serves as the building block of the nervous system transmitting electrical and chemical signals throughout the body 

• consists of the cell body (soma), dendrites, and axon 

Glial Cells 

the support cells of the nervous system proving structural support, insulation, and nourishment to neurons

Motor neurons (efferent neurons) 

nerve cells that transmit signals from the CNS to muscles, glands, organs, initiating and controlling movements 

Sensory Neurons (afferent neurons)

specialized nerve cells that transmit sensory information from sensory receptors, such as those in the skin, muscles, and organs to the CNS

Interneurons

nerve cells that serve as connectors within the CNS relaying signals between sensory neurons and motor neurons

Reflex Arc

neural pathway that controls reflex actions, allowing for rapid, automatic responses to sensory stimuli without conscious thoughts (primitive reflexes)

Endocrine system 

a system of glands and organs that produce hormones and release them into the bloodstream to control many functions in the body 

Hormones

chemical messengers produced by glands in the endocrine system that travel through the bloodstream to target cells or organs where they regulate various physiological processes and behaviors 

Melatonin

hormone that regulates the sleep-wake cycle and circadian rhythms in the body

Oxytocin

hormone and neurotransmitter that plays a key role in social bonding

Adrenaline

hormone and neurotransmitter that plays a key role in the body’s stress response often referred to as the flight/flight response

Norepinephrine

neurotransmitter that functions as both a hormone and a neurotransmitter in the body. It is involved in the body's "fight or flight" response, regulating arousal, attention, and stress.