What is homeostasis? -The process of maintaining a constant internal environment despite a constantly changing external environment

What is dynamic equilibrium?

Dynamic=

Equi=

***Remember, Homeostasis is an ONGOING process. Your body levels/requirements are ALWAYS changing…Nothing in your body is ever “standing still” !!!!

System Role in Homeostasis

Excretory -Removes metabolic wastes and Regulates bodily fluid levels

(H2O level, salt level)

Nervous -Regulates body functions through electrochemical impulses (messages)

Endocrine -Regulates body functions and Behaviors through chemicals

(hormones)

(nerve control)

Respiratory -Regulates O2 and CO2 levels (gas exchange)

Circulatory -Regulates the transfer of materials in the blood (O2, nutrients, waste)

Digestive -Regulates and provides the end products of food usable for cell functions

(glucose, amino acids, fatty acids and glycerol)

Immune -Regulates and protects the body from disease and microorganisms

**Remember that single-celled organisms use organelles to carry out life processes while multi-cellular organisms use body systems.

What is thermoregulation and how is it regulated? -The ability to maintain a fairly constant internal body temperature

Regulated by: Too Hot=

Too Cold=

How do animals survive in the cold?

How do humans survive in the cold?

-The product of a system shuts down or limits the system A change occurs producing

another change

(remember your home heating system)

-Blood Sugar Level Insulin/Glucagon Levels

-Menstrual Cycle Estrogen/FSH Levels

-Breathing Rates O2/CO2 Levels

How is water balance maintained in humans?

-Urination

-Perspiration

How is water balance maintained in plants? -Guard Cells (open/close stomate)

Where does this occur in the plant?

- The underside of the leaf (top part of leaf is waxy)

Too much water

Stomate OPENS

Guard cells curved

Not enough water

Stomate CLOSES

Guard cells straighten

When do most keep their stomates open/closed?

-Most green plants keep stomates OPEN during The day to take in CO2 and release O2 for Photosynthesis. They CLOSE at night

-Desert Plants (cactus) keep their stomates CLOSED during the daytime to conserve H2O. They OPEN at night to take in CO2 for Photosynthesis to occur the next day

What gases are involved in human gas exchange?

1. When CO2 INCREASES, blood becomes acidic (low pH)

How are breathing rates regulated?

2. The hypothalamus detects the pH change

3.Effectors in the medulla make the necessary adjustments to maintain homeostasis of the O2/CO2 levels in the blood

Possible Adjustments: - Increase/decrease breathing rate -Increase/decrease heart rate -Increase/decrease depth of breath (deep/shallow)

When CO2 level decreases, pH increases (remember normal blood = pH 7)

Breathing and heart rate return to NORMAL

What are some internal conditions maintained by Homeostasis (dynamic equilibrium)?

-pH, temperature, water level, salt level, O2/CO2 levels

What happens when homeostasis is DISRUPTED?

What are the factors that cause disease?

-Genetic; From parent to offspring

Ex: 1. Sickle Cell Anemia

-Hemoglobin is flawed causing RBC to become twisted, making it difficult to travel through capillaries. Poor Oxygen supply. No cure, treated with blood transfusions.

2. Hemophilia -Damaged platelets. Can’t Form blood clots. May bleed to death. Treated With platelet transfusions, not cured.

(Disease causing microorganisms)

-Infectious disease that is passed from person to person. May be contracted through the respiratory tract, digestive Tract, urinary tract, or breaks in the skin.

Ex: 1. Bacteria- Bronchitis, Tuberculosis

2. Fungi- Athlete’s Foot

3. Parasite- Malaria, tapeworm

4. Virus- HIV, Influenza

-Biological Pollutants

Ex: mold, mildew, mites, animal dander -These can lead to asthma

-Chemical Pollutants

Ex: Lead, coal, asbestos, mercury

-can cause learning disabilities, behavioral problems, seizures, coma, cancer, and even death

-Harmful substances that disrupt Homeostasis in various different ways

-An organ stops performing it’s normal function

Ex: 1. Heart Failure

2. Kidney Failure

-Living a lifestyle involving smoking, alcohol, Drugs, poor diet, lack of exercise, unsafe sex Can lead to disease

Ex: Some include: HIV/AIDS, STD’s, lung cancer, skin cancer, heart disease, hypertension, diabetes

How can microorganisms (foreign invaders) enter the body? -Nasal cavity, skin, digestive tract (food)

How does the body protect against disease?

Physical and Chemical Barriers

1.Skin and membranes

-Major physical barrier. Layer of flat, tough Cells that keep microorganisms out UNLESS DAMAGED

-PHYSICAL BARRIERS:

CHEMICAL BARRIERS:

1.Tears, saliva, and sweat

-contain chemicals that kill or inhibit some bacteria

2. Mucus -entraps pathogens

3. Stomach Acid

-destroys many pathogens in food

1. Inflammatory Response: -When injury occurs, damaged cells send out Chemicals that act as an alarm and cause an Increase in blood flow to that area

-Redness, swelling, pain, and warmth occur

2. White Blood Cells (Macrophages): -Giant white blood cells that ingest bacteria

(Engulf and destroy)

Immune System

-maintains homeostasis by protecting the body from disease through recognizing, Remembering, attacking, and destroying pathogens

How do WBC work? 1. Engulf and destroy- Surround, digest, and kill pathogen

2. Produce antibodies- Proteins that attack and kill Antigens (shape specific)

3. Recognizes and remembers-

Recognizes and remembers Previously encountered Pathogens and is better prepared to fight them

pathogen

WBC

Antibodies

WBC

WBC destroying marked pathogen

How does the human body respond when a pathogen or infection enters?

What is an antigen?

-any substance that can cause an immune response

Antibodies are SPECIFIC to antigens

-they are found on the surface of pathogens (as well As every cell in your body!)

Ex: Viruses, bacteria