Animal Systems: REGULATION
Nervous System
The nervous system maintains homeostasis (an internal stable environment) by…
Functions of the Nervous System
1.
- uses receptors to gather information from all over the body
2.
-the brain then processes the information into possible responses
3.
-sends messages back through the system of nerve cells to control body parts
Evolutionary Trends of the Nervous System
Animal
Taxon
Type of
Nervous
Tissue
Aquatic Invertebrates
Flatworms &
Roundworms
Segmented Worms &
Arthropods
Vertebrates
A simple system with
interconnected neurons
called
; contain
specialized cells for touch
and chemical detection
(a group of
nerve cells) and nerve
cords run along the
body; can detect
chemicals, touch, and
some have eyespots
occurs
which is the
concentration of nerve
cells in a head region to
form
; intense
senses in arthropods
A well-developed brain
evolved from the spinal cord;
the size and complexity
increases from
.
planaria, flukes,
earthworm, ants,
mammals, birds, reptiles, fish,
tapeworm, hookworm
grasshopper, bees
amphibians
Picture of
system
Examples
sponges, jellyfish, hydra
Structure of the Nervous System:
Neuron –
1.
- the largest part of the neuron;
contains the nucleus and organelles
2.
- short, branching extensions
spreading out from the cell body; receive and carry impulses to the cell body
3.
- long, fibrous part of neuron; conducts nerve impulses away from cell body
What is a nerve impulse? An
signal is sent from the
dendrite, along the axon, to the terminal. A
message,
called a_____
_______
is released from the axon
terminals into the
_______
, where it travels to the next
cell.
**Flow of Impulse: _____________  cell body (nucleus) _______  jumps
synapse  next dendrite**
Types of Neurons
a.
neurons carry messages from sense organs to the brain/spinal cord(CNS)
b.
neurons carry impulses from the brain/spinal cord (CNS) to the muscles/organs.
c.
carry impulses between sensory and motor neurons (within the CNS).
Reflexes:
They are ______________________, happen very quickly, take place _____________ the brain receiving the
message, they protect you by triggering an involuntary response to stimuli (stepping on a tack).
Divisions of the Nervous System (CNS and PNS)
I.
Central Nervous System (CNS) – derived from dorsal nerve cord
A. Brain- “control center”- _______________ and analyzes
information; processes and sends back instructions
Cerebrum: controls ______________, language, learning/studying,
judgment, & voluntary actions
Lobes of the Cerebrum: write what each lobe does….
•
•
Language and Speech – strokes, tumors, injuries
Broca’s Area:
– Primary motor cortex in the ______________ that
controls muscles
– Damage to area means you can understand language
but are unable to speak it
• Responsible for speech generation
Ex –
stroke patients
Wernicke’s Area:
• The posterior part of __________________
• Damage to area means you can speak but unable to
comprehend speech
• Responsible for hearing speech
Cerebellum: controls _____________________ functions of muscles and maintains ________________
Hypothalamus: Controls ____________________ in body (body temperature, water balance, hunger,
thirst, biological clock, flight or fight response)
Brain Stem: controls involuntary functions
Medulla Oblongata & Pons: controls basic primitive body functions such as
__________________, heart ______________, blood pressure, etc.
II.
Peripheral Nervous System (PNS)
A. Consists of nerves outside the CNS.
Nerves:
B. Gathers information and ______________________ it to and from
______________
C. PNS divided into two systems:
1. ___________________(voluntary)
2. ___________________(involuntary)
Autonomic Nervous System – the_________________________branch of the
nervous system
 Divided into two division:
 _________________ division
 _________________ division
 Sympathetic – “Fight-or-flight”
 Response to unusual stimulus
 Takes over to _______________activities (increase heart rate, blood pressure, blood sugar
level, dilates bronchioles in lungs, dilates
pupils)
 Parasympathetic – “Rest and Digest”
 Chiefly concerned with promoting normal
digestion and elimination of feces and urine
and with conserving body energy ( normal
low levels of heart rate, blood pressure, etc.
pupils constrict)
Levels of Organization
Interaction with other systems for Regulations
 Bones of the
protect the spinal cord and brain.
 The brain controls heart rate, blood pressure, and breathing via the
and
.
 Glands in the brain control the release of hormones of the
and
systems.
 The brain controls muscles both in
and
.
Diseases and Disorders of the Nervous System
1. ___________________- a virus that attacks the spinal cord; eventually causes paralysis
2. _________________________________ (MS)- affects neurons; slows nerve impulses, causing muscle
weakness, possibly paralysis.
3. ___________________________________- brain tissue deteriorates; severe memory loss
4. _______________- a blockage in a blood vessel in the brain, causing brain damage
5. ______________________- a bruise to the brain when the brain hits the inside of the skull
Fun Facts
 A human body contains more nerve cells than there are stars in the Milky Way
 Neurons are the largest cell in the body and do NOT undergo mitosis
 Nerve impulses move at 100 meters per second or more
 Longest axon of a neuron is 15 ft! (in the giraffe)
Animal Systems: REGULATION
Regulation requires
- the ability of the body or a cell to seek and
maintain stability within its internal environment when dealing with external changes
The nervous system maintains homeostasis by…
The excretory system regulates the concentration of water and other components of body fluids like salts and
nutrients.
Every organ system plays a role in maintaining the constancy of the internal environment.
– Examples:
Homeostatic Control Mechanisms
• __________________ within the body is essential for homeostasis.
• Homeostasis is accomplished primarily by:
– Endocrine system (hormones)
– Nervous system (electrical signals)
Negative Feedback vs. Positive Feedback Mechanisms
 Negative Feedback Mechanism – The net effect of the response to the stimulus is to shut off the
original stimulus or to _______________ its intensity.
– Examples: Thermostat or body temperature, heart rate, blood pressure, breathing rate, blood
levels
 Positive Feedback Mechanism – Feedback that tends to cause a variable to change in the same
direction as the initial change; __________________ the stimulus
– Examples: Blood clotting, birth of a baby
– More __________ in the body
The Excretory System
Evolutionary Trends:
Animal
Taxon
Release
Wastes By…
Picture of
system
Aquatic Invertebrates
to
remove waste across their
cell membranes directly
into the water
Worms and Mollusks
Use of
_____________________tiny pores along the body
excrete waste
Insects
Vertebrates
Using
__________________to
collect and excrete
wastes
Use of kidneys, ureters,
and a bladder to collect
and excrete waste
Function- Maintains Homeostasis in 3 Steps:
1.
- Filters substances from the blood
2.
- Regulate the chemical composition of body fluids by retaining
the proper amounts of water, salts, and nutrients
3.
- Elimination of wastes in the form of urine
Major Organs:
 Kidneys (renal = kidney)
o _____________ organs that receive blood via the
o The main filters are tissues called
that separate the components of the blood
o Every 45 minutes ______________ filter all the __________________in your body
o Filtered blood leaves kidneys and returns to circulation carrying nutrients, salts, and water via the
o Excess _____________ and toxic waste in the form of ______________ leave the kidney via the
______________________
o Urea is a waste product found in __________ – it contains excess _________________ and is the
result of protein ________________________.
o Sometimes excess ____________ or minerals in the urine crystallize and form
___________ . When kidney stones block the
, they cause great
pain.

Ureters—tubes that carry urine from

Bladder—muscular sac where

Urethra—tube that carries urine from
to urinary
is temporarily stored before being excreted
to _________________ the body.
Levels of Organization within the Excretory System
renal cells
nephrons
kidney, bladder, ureter, urethra
excretory
Organism

Respiratory system (lungs) remove CO2 from blood. Circulatory systems (blood) brings wastes to lungs,
kidneys, skin for excretion. Integumentary system (skin) excretes water, urea, salts, through sweat.