Transcript Biology B - Miss Collins' Science Classes

Unit 6: How the Nervous and
Endocrine Systems Regulate the
Human Body and Maintain
Homeostasis
CELLULAR ORGANIZATION
1. Cell: smallest unit of lifeneuron
2. Tissue: a group of similar
cells that work together to
perform a similar functionnerve tissue
3. Organs: two or more types
of tissues that function
together- brain
4. Organ System: two or
more organs that work
together- brain & spinal
cord make up the central
nervous system
5. Organism: all of the organ
systems working together
to maintain life and
homeostasis- human
MECHANISMS OF HOMEOSTASIS
Why is homeostasis so important? Why must it be
maintained? Review from unit 1
 How it works:

Sensors:
gather information on
internal/ external
conditions
Targets:
Control Center:
Organs and tissues
respond to messages to
restore homeostasis
receives the information,
compares to set points,
and sends messages
Communication System:
Nerves and hormones
carry signals to targets
EXAMPLE: DEHYDRATION
Sensors:
Hypothalamus (brain)
detects that there is too
little water in the blood
Targets:
Because of the ADH, the
kidneys filter out less
water as waste/urine
Control Center:
Endocrine System signals
the pituitary gland
Communication System:
Pituitary gland releases
ADH
COMMUNICATION SYSTEMS OF THE BODY
Nervous System
Endocrine System
Quick reactions
 Connected system
 Brain, spine, and nerves
 Electrical & chemical signals
 Immediate processes

Slower reaction rate
 Isolated organs
 Glands and blood stream
 Chemical signals
 Longer-term processes

Both
Communication systems
 Stimulates other tissues
 Produces responses to stimuli
 Use chemical signals
 Maintains homeostasis

THE NERVOUS SYSTEM: CENTRAL & PERIPHERAL
THE NERVE IMPULSE
NEURONS AND THE BRAIN
THE SENSES
Sensory Organs work with your brain to gather information
about the world around you so you can react accordingly
 Sensory Organs include:

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Eyes- photoreceptors that detect light and color
Ears- mechanoreceptors that detect sound waves
Nose- chemoreceptors that detect airborne chemicals
Tongue- chemoreceptors that detect chemicals dissolved in saliva
Skin- thermoreceptors that detect temperature AND pain receptors
that detect pressure
Incoming information from the sensory organs travel through
nerves to the cerebrum where the input is processed
SIGHT
SOUND
SCENT
TASTE
TOUCH
THE RUBBER HAND:
WHICH SENSE DOES YOUR BODY RELY ON MOST?
WHAT!?! HOW CAN MY BRAIN BE SO EASILY TRICKED?
THE HUMAN NERVOUS SYSTEM, PART I
THE HUMAN NERVOUS SYSTEM, PART II
NEUROTRANSMITTERS
WHAT HAPPENS WHEN THERE IS A CHEMICAL IMBALANCE?

One very common chemical imbalance in the brain is a
mood disorder:
Depression is the most common mood disorder
 It is treated with an SSRI- selective serotonin reuptake inhibitor
 The SSRI helps compensate for underactive serotonin producers
by blocking the receptors from reabsorbing extra serotonin

ADDICTION AND THE BRAIN
This is True of ALL Mood Altering Substances,
including alcohol, THC, MMDA, Cocaine, etc…
ENDOCRINE SYSTEM
PARTS OF THE ENDOCRINE SYSTEM
Gland/Organ
Location
Secrets Hormones that Control
Hypothalamus
Brain
Growth, stimulates reproductive
maturity
Pituitary
Brain
Growth, water balance in the blood
Thyroid
Neck
Metabolism, growth and
development
Thymus
Chest
Maturation of white blood cells
Adrenal Glands
Above the kidneys
Blood pressure, breathing rate,
“fight or flight” response
Pancreas
Between the intestines
and the stomach
Digestion and glucose metabolism
Gonads
Pelvis
Reproductive development and
functions
RESPIRATORY SYSTEM
CIRCULATORY SYSTEM
VASCULAR SYSTEM
The vascular system, which consists of arteries, veins, and
capillaries, works with the respiratory and circulatory
systems to help your body maintain homeostasis
 All of the body’s blood vessels:

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Have an epithelial layer
Transport blood, gasses, and other materials
Are found in all parts of the body
Are all part of the circulatory system
If there’s one thing ladies love, it’s a vascular man!
ARTERIES
The arteries carry blood AWAY
from the heart bringing
oxygen-rich blood to cells
 Arterial Structure:

Three Layers
 Muscular and Elastic to keep
blood moving

VEINS
The veins carry blood TO the
heart carrying oxygen-poor
blood away from cells
 Venous Structure:

Larger diameter
 Have valves
 Needs muscle activity to keep
blood moving- DVT

CAPILLARIES
The capillaries carry blood BETWEEN the cells and the
veins and the cells and the arteries. They carry both
oxygen-rich and oxygen-poor blood
 Capillary Structure:

Only one unicellular layer thick
 Form dense capillary beds
 Materials diffuse in and out of them

BLOOD
BLOOD TYPING
LYMPHATIC SYSTEM
Collects fluid from the
circulatory system, filters
and cleans it, and returns
it to the blood stream
 Works with the immune
system to protect the body
from potentially harmful
pathogens
 The body’s skeletal
muscles contract around
the lymph vessels to keep
the lymphatic fluid
moving forward- never
backward!

IF THERE IS A MALFUNCTION IN THE LYMPHATIC SYSTEM…

If the fluid is not returned to the circulatory system:
There will be too little plasma.
 If there is too little plasma, platelets will stick together and possibly
cause an unwanted clot.
 This can lead to a Heart attack or Stroke

If the fluid is not filtered and pathogens aren’t destroyed, you
will get very ill.
 If the fluid does not keep moving and does not drain properly:


Edema:
IN SUMMARY…

You body consists of many, intertwined systems:
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Central Nervous
Peripheral Nervous- Somatic, Autonomic, Sympathetic, and
Parasympathetic
Endocrine
Circulatory
Respiratory
Lymphatic
The body communicates with itself electrically (nerves) and
chemically (hormones and neurotransmitters)
 Each system works together to maintain homeostasis- the
delicate balance ensuring the optimal conditions for life

AWESOME VOCAB!
Thermoregulation: process of maintaining a steady body
temperature under a variety of conditions
 Endocrine System: a collection of physically disconnected
organs that helps to control growth, development, and
responses to your environment, such as body temperature
 Nervous System: physically connected network of cells,
tissues, and organs that controls thought, movements, and
simpler life processes such as swallowing
 Stimulus: something that causes a response
 Axon: a long extension that carries electrical messages away
from the cell body and passes them to other cells
 Resting Potential: the difference in charge across the
membrane

AWESOME VOCAB!
Addiction: the physiological need for a substance
 Hormones: chemical signals made by the endocrine system
 Dendrites: branchlike extensions of the cytoplasm and the cell
membrane that receive messages from neighboring cells
 Action Potential: a moving electrical impulse
 Veins: blood vessels that carry blood from the rest of the body
back to the heart
 Reflex Arcs: nerve pathways that need to cross only tow
synapses before producing a response
 ABO Blood Group: type O has no protein marker and can be
donated to a person with any other blood type. Type AB blood
has both protein markers and can accept any type of blood
 Pulmonary Circulation: occurs only between the heart and
the lungs
