Science II

Created: June 25th, 2026

Animals use a complex system of tissues called a

nervous system

What do animals use their nervous system to do (behavior)

respond to their internal and external environment through behavior

All types of behavior are regulated by what system

nervous system

What can be thought of as the control center of an animal

nervous system

Only a few animals such as what, lack a nervous system

sponges and some species of aquatic worms

What are the two main parts of a nervous system in an animal

central and peripheral

What parts of the body comprise the central nervous system

brain and spine

What is another name for the peripheral nervous system

outer system

What is the name for the individual cells that make up the nervous system

neurons

What is responsible for the transmission of electrical impulses

Neurons

Electrical impulses in the nervous system are mediated by what

neurotransmitters

What are neurotransmitters

chemical molecules released by neurons

Collections of neurons that extend out from the central nervous system form what

nerves

The ends of these neurons (nerves) form fiber-like structures typically found where

peripheral nervous system

Neurons can transmit info both to and from the brain in how much time

milliseconds

Neurons range in size from ____ to ____ in length

millimeters, meters

Neurons have ______ that reach out to other neurons by releasing specific ____ cues that either _____ or _____ other neurons, which serves to ____ or _____ the strength of the signals

projections, chemical, attract, repel, strengthen, diminish

Neurons in the central nervous system do not typically

regrow

Nerves where, have the capacity to regrow

peripheral nervous system

What is the term for the physical detection of stimuli

sensation

The range of what an animals is capable of sensing varies depending on what

the species

Mice have the ability to sense sounds at which frequencies that humans cannot

ultrasonic

What term is used to refer to the process of converting sensation to interpret and react to the environment by expressing behavior

perception

What is referred to as the physical record of information

sensation

Perception is based on the _____ and _____ of an individual

memory and learning

Which animals possess the most complex nervous systems found in any life form on Earth

Vertebrae animals

The vertebrae nervous system evolved around how many years ago

500 million

What do vertebrae animals possess (series of bones)

spinal column

The spinal column in vertebrae animals provide _____ to the nerves and neurons and provides ______ _____ to the rest of the nones in the body

protection, structural support

Inside the spinal column there Is a bundle of nerves called what

spinal cord

What does the spinal cord do

transmits sensory information from the body to the brain and motor command from the brain to the muscles

The spinal cord transmits sensory information from the _____ to the _____

body, brain

The spinal cord transmits motor commands from the _____ to the _____

brain, muscles

The spinal cord is responsible for what type of behaviors (instinctual)

reflexive

The spinal cord controls _____ and ________ movements

voluntary, involuntary

The vertebrae nervous system is comprised of what 2 parts

the peripheral nervous system and the central nervous system

The peripheral nervous system is broken down into the _____ and _____ systems

somatic, autonomic

Which part of the vertebrae nervous system is responsible for communication

peripheral nervous system

Which part of the vertebrae nervous system is responsible for control

central nervous system

The peripheral nervous system transmits sensory info to the ______ and _____

spinal cord and brain

Peripheral nerves cannot produce behaviors own their own outside of immediate ________ ______

involuntary behaviors

What re the two main functions of the somatic nervous system

receive sensory input and control movement

Sensory inputs in humans include what 5 things

sound, smell, touch, sight, tastes

Sensory inputs in some animals can include other 3 things

electrical fields, polarized light, magnetic fields

Each sense requires a specific set of neuron receptor types called what

somatosensory neurons

Pain receptors are called what

nociceptors

Nociceptors can detect different kinds of ____ and ____

pressure and temperature

Nociceptors can trigger _____ without having to ____ ____ __ ___ _____

reflexes, relay messages to the brain

Rather than transmitting to the brain, nociceptor's messages are relayed where

spinal cord

Behaviors that occur without thinking are called what

reflexes

Sensations from neurons in your muscle sending information back to the brain in order to help the brain determine where you are in space is called

proprioception

T/F Your hands and face are more sensitive than your back

True

What nervous system is responsible for processes such as breathing and heart rate

autonomic nervous system

What nervous system is constantly working in the background

Autonomic nervous system

What 2 parts comprise the autonomic nervous system

sympathetic nervous system and the parasympathetic nervous system

What does the sympathetic nervous system do

puts the body in a state of arousal and heightened alert

What does the parasympathetic nervous system do

acts in the opposite manner by relaxing the body

The sympathetic nervous system has been called the what

fight or flight

The sympathetic nervous system is controlled primarily by which part of your body

spinal cord

To prepare for potential bodily harm the sympathetic nervous system trigger a _____ _____ ______ response to repair things quickly

quick immune system

T/F the sympathetic nervous system is not present at birth

False

T/F the sympathetic nervous system is energetically costly

True

What is the nickname for the parasympathetic nervous system

rest and digest

Once danger is dealt with the body recovers by reducing _____ ___

heart rate

When an animal is in a heightened state of alert, behaviors such as _____ and ____ are suppressed

feeding and mating

The constant activation of the sympathetic nervous system affects the animal's ______ _____ by limiting the ______ response

immune system, inflammation

The long term activation of the sympathetic and parasympathetic nervous systems are believed to the be the triggering factor for many ______ ______

autoimmune diseases

The involvement of the ____ is required for animals to perform all behaviors with exception of reflexive

brain

What is the main highway that connects the brain to the peripheral nervous system

spinal cord

If the spinal cord is damaged it can cause what

paralysis

Vertebrates' central nervous system is well protected by fluid called

cerebrospinal fluid

What connects the brain to the spinal cord

brain stem

The ______ is responsible for relaying messages from the brain to the rest of the body for autonomic nervous system activation

brainstem

What is the name for the layer of cells surrounding the blood supply in the brain that only allows specific molecules to enter and exit the brain

The blood-brain barrier

What does the blood-brain barrier do

allows specific molecules to enter and exit the brain

Thanks to what, are brain infections rare

blood-brain barrier

The vertebrate nervous system evolved from the

invertebrate nervous system

T/F The invertebrate nervous system is much less complex than the vertebrate nervous system

True

Invertebrates lack ____ ___ and ____ to protect their central nervous system

hard bones, spine

T/F Invertebrates' nerves are often much smaller and greater in number compared to that of vertebrate animals

False, Larger and fewer

What is the scientific name for sea slugs

Aplysia californica

Why have scientists extensively studied sea slugs

their neurons are large enough to visualized without a microscope

Jellyfish are an example of animals that do not have a _______ ______ ______ yet are able to respond to their environment and engage in behaviors

central nervous system

What is the simplest neural organization

nerve net of radiates

What is the simplest linear type nervous system of two nerves connected to a complex neuronal network

Flatworm system

What type of nervous system is organized into bilobed brain and ventral cord with segmented ganglia

Annelid nervous system

Insects have some complexity to their nervous system but still lack what is classified as a

central nervous system

Which invertebrates have the most complex nervous systems

cephalopods

Cephalopods include what animals

squids and octopuses

Cephalopods have how many neurons and large central brains

hundreds of millions

T/F invertebrates are often quite big

False, they are often small

T/F invertebrates do not eat often and have small lifespans

True

What are hormones

chemical signals that carry messages through the body to specific target tissue

Hormones are released by glands called

endocrine glands

Hormones created within the body are called

endogenous hormones

Hormones obtained externally are called

exogenous hormones

T/F invertebrates have specific hormones specific to them

True

Hormones are considered ____ acting

slow

Whyt are hormones considered slow acting

they must first be released bu endocrine glands and travel to receptors in other target tissue

Hormones circulate in your

blood