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Human Body Systems

standards 9-10

Major Organ Systems of the Body

Digestive- extracts and absorbs nutrients from food

Respiratory-obtains oxygen, releases carbon dioxide

Nervous-collects and evaluates information and issues commands for a quick response

Circulatory-transports oxygen, carbon dioxide, nutrients, and cells

Endocrine-secretes chemicals called hormones

Major Organ Systems of the Body

Immune- defends against pathogens and cancer

Muscular-movement

Skeletal- protects and supports the body

Urinary/Excretory- removes wastes from blood, regulates concentration of the body’s fluids

Reproductive- produces gametes, nourishes and shelters fertilized egg (females)

FOUR PRIMARY FUNCTIONS OF

NERVOUS SYSTEM

1. Sensing the world

Vision, Hearing, Smell, Taste, Touch

2. Transmitting information

3. Processing information

4. Producing a response

Nervous SystemEnables us to communicate with and

react to the environment and perform our life activities

Has two main divisions

Central Nervous System

( CNS)

Peripheral Nervous System

( PNS)

Central Nervous

System

Brain

Cerebrum

Cerebellum

Brain Stem and

Pons

Lobes (4)

Spinal Cord

“information

superhighway”

Peripheral

Autonomic

Sympathetic

Fight or Flight

Parasympathetic

Relaxation

Somatic

Sensory and Motor

Nerves

Reflex Arc

Parts of the

Nervous System

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Central Nervous System

Has two main divisions

Brain: main control center

Spinal Cord: connects and relays

nerve impulses to and from the

brain.

•Smaller part of the brain ,towards the

back

FUNCTIONS:

•Coordinates all movement

•Helps maintain posture, muscle control,

and balance

Large front part of the brain

FUNCTIONS:

Voluntary activity

Memory

Language

Receives and responds to sensory signals

Controls motor functions

BRAIN STEM

swallowing, coughing,

sneezing, and

vomiting

Includes the

Medulla Oblongata

PONS

Breathing

Heart rate

Internal Organs

Medulla

• Damage in this area

will usually kill you.

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“controls: emotions and memories”

Damage to

these areas

can lead to

amnesia or

emotional

disturbances

Stores: experiences and/or learning

Frontal-

behavior &

emotion

Temporal- memory & emotion

Occipital- vision

Parietal-

Sensory info

The functional unit of the

nervous system is the

nerve cell, the NEURON

They send

electrochemical

messages around the

body

Glial cells provide support

and protection for neurons

The Nervous System

The gap from the

nerve endings of

the axon to the

dendrites of the

next neuron is

known as a

synapse

Peripheral Nervous System

AutonomicControls muscles and organs within

the body

Fight or Flight

Rest and Digest

Peripheral Nervous System

SomaticSensory nerves:

conduct nerve

impulses toward the

central nervous system

Motor nerves: conduct

impulses away from

the central nervous

system

Reflex Arc

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Reflex Arc“ what happens when you step on a nail”?

Reflexes are automatic

The Stimulus (nail ) is received

by the sensory neurons in the

foot

This info travels to the spine,

where the interneuron is triggered

The interneuron stimulated the

motor neuron, to move the foot

A progressive wave of electric and chemical activity along a nerve fiber

that stimulates or inhibits the action of a muscle, gland, or other nerve cell

*This is how the information moves from sensory neurons to interneuron

to motor neurons

Endocrine SystemThe body’s slower, chemical

communication system

What does the Endocrine System Do?

Uses chemical signals for cell to cell communication – this is why it is slower than the nervous system

Coordinates the function of cells – e.g. cells in the uterus need to know when cells in the ovaries are active

Responds to information from the brain to keep body chemistry balanced- homeostasis

Glands of

the

Endocrine

System

and their

location

What do these glands influence?

Hypothalamus: The master control gland that is located in the brain

Pituitary Gland: The 2nd master gland –that reacts to the hypothalamus, affects growth and controls other endocrine glands

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Thyroid gland – can

increase protein

production and oxygen use

by cells. Also regulates

calcium levels

Pancreas – regulates the

level of sugar in the blood

by secreting insulin.

Thymus – helps the body

make a type of white blood

cell. These cells help

protect you from infections.

What do these glands influence?

Pineal --secretes

melatonin helps to

regulate daily

biological rhythms

and promotes

sleep.

Ovary – secretes

female sex

hormones such as

estrogen

Testes – secrete

male sex hormone

such as testosterone

aka: Androgens

Adrenal Gland -

secrete epinephrine

and norepinephrine

(aka: Adrenaline )

which help to arouse

the body in times of

stress (fight or flight

responses)

How are the brain and hormones connected?

Negative feedback loop

(like a thermostat)

Glands

Body

Brain

HOMEOSTASIS –balanced internal environment

Controlling Body Temperature

high

low

nerve signals

sweat

nerve signals

body temperature

(37°C)

shiver

dilates surfaceblood vessels

constricts surfaceblood vessels

Feedback

hypothalamus

hypothalamus

Immune System“The Triple Threat”

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What are some ways that you might be

exposed to a pathogen?

Direct contact

Ø Shaking hands

Ø Sexual contact

Indirect contact

Ø Coughing and sneezing

Ø Touching contaminated surfaces

Water and food

Animal bites

Non-specific Defenses

Clearance

Øsneezing and

coughing

Secretion

Ømucous

membranes

Cellular defenses

Øskin and

epithelium

Øphagocytosis

Specific Defenses

Humoral

Anti-body

mediated

Cell mediated

IMMUNE SYSTEM

( The Triple Threat) 1st Line of Defense

ü Skin

ü Oil/ Sweat

ü Mucous Membranes

2nd Line of Defenseü Temperature

ü Chemical Signals

ü Inflammatory

3rd Line of Defenseü Lymphocytes

ü Macrophages

Pathogens

Something that causes an infectious disease

Any foreign substance that invades the body is called an Antigen

virus bacteria fungi protists invertebrates

What’s a LYMPH? Lymphatic system makes & stores White

Blood Cell’s (WBC)

WBC’s are made in red bone marrow

Lymph nodes are areas of tissue that store

WBC’s

WBC’s are also called leukocytes

5 Types, vary based on function

First defense against invasion by

pathogens is the SKIN

ØOil and Sweat make the skin’s surface very

acidic, slowing the growth of pathogens

All body openings are lined with Mucous

ØCreates a sticky chemical barrier that

pathogens get stuck in.

1st line of defense(Barriers)

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2nd line of defense(The Inflammatory Response)

Chemical Response

l Suppresses infection and speeds healing

l When there is an infection or injury cells

release chemical alarm signals

l Starts a chain reaction of four steps1.Histamine make blood vessels expand and leak

2.Phagocytes are released

3.Phagocytes engulf (eat) bacteria and dead cells

4.Platelets move out of the capillary to seal the

wound.

2nd Line of Defense(The Temperature Response)

•When macrophages/phagocytes attack they

send messages to the brain to increase the

body temp (FEVER)•Phagocytes move faster at higher temperatures

•Bacteria do not grow well at high temperatures

(Humoral and Cell Mediated)

Lymphocytes (white blood cell) fight against pathogens

Helper T Cells recognize the antigen and alert the body to produce Killer T Cells

B Cells make antibodies that bind to the antigens

Killer T Cells search for antibodies and seek and destroy

Macrophages identify pathogens, eat them, and then display their antigen

Ø Can eat 100s (hundreds) of cells at a time

3rd Line of Defense Acquired Immunity

Body’s resistance to previous pathogens

Immune response is faster because your

body has memory cells that remember

how to fight off the pathogen

Allergies

The body reacts to a harmless

substance as if it were a pathogen

Allergies get worse because the body

produces antibodies and then fights

even harder the second time around!

•Macrophages release

histamine, which causes

inflammation

•Treat with antihistamines

Autoimmune Disease

The body doesn’t recognize itself and

produces antibodies against its own cells

and tissues

ü Lupus

ü Asthma

ü Multiple Sclerosis

ü Juvenile Diabetes

Treat many of these with drugs to slow down

immune system

But this makes them get sick more often

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HIV (human immunodeficiency virus)

Attacks helper T cells

number of helper T cells becomes so

low the body can’t fight disease

Less than 100 Helper T Cells and a

person has AIDS

Person dies because the body can’t

destroy the pathogens

Immune Diseases

Immunization/Vaccinations

Introduces the body to the antigen in a

way that doesn't make a person sick

Allows the body to produce antibodies

that will then protect that person from

future attack by the germ that causes

particular disease.

EX: Measles Vaccine

Antigen- Antibody

ResponseInfection Wars

Can get

blood

from

O and A O and B A, B, AB, and

O

O

Can give

blood to

A and AB B and AB AB A, B, AB, O

Viruses and Bacteria

§ Means: Poison

§ Cause disease in animals, plants, & bacteria

§ Nonliving (not made of cells)

§ All viruses have at least 2 parts:

§ DNA or RNA core

and a protein coat or

lipid coat

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§ Need a host cell to replicate

§ Replicate immediately or after a long time

§ Infect the cell using a bacteriophage

Most can’t be cured

§ Antiviral drugs relieve symptoms, but

don’t kill the virus (like cold sore med’s)

§ Antibiotics don’t work on virus

Vaccines are made from weak viruses

Cause your immune system to make antibodies

that can kill the virus if exposed again

Vaccines can stop some viruses like flu,

chicken pox, measles

How do antibodies help destroy

Pathogens?

Three ways:

Cause them to burst

Inactivate the pathogen to make it harmless

Cause them to clump together so a phagocyte

can eat them.

Bacteria are called “monerans”

Some cause disease & some are good

Living (made of cells)

Prokaryotes (no nucleus)

Most have a cell wall (like plants)

Flesh Eating Bacteria

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§ Reproduce very quickly

§ Don’t need a host to reproduce

§ Many can survive in harsh conditions by

forming endospores (thick wall)

§ Antibiotics

§ Interfere with the bacteria’s life

processes, like metabolism.

§ Eats holes in the cell wall.

If you don’t take it, for all 10 days, you

only kill the weak bacteria

Bacteria are able to digest the antibiotic

Linked to:

Addition of antibiotic to cattle feed

Over-prescription

1 million ton/ 50 years

§ Decomposers

§ Help animals and humans digest food

§ Can be used by humans to make

products (food products, medicine, etc.)