Living Environment Regents Exam Review - Unit 4

Unit 4 Review

nutrition

• function: to change large, organic compounds (food) into small, soluble molecules that can cross cell membranes

• body system: digestive system

• disorder/malfunction: ulcers, diarrhea, constipation, appendicitis

excretion

• function: to get rid of cell/metabolic wastes

• body system: excretory system

• disorder/malfunction: kidney stones, kidney failure

transport

• function: to move materials around the organism to each cell of the body (including nutrients, wastes, hormones, O2, CO2)

• body system: circulatory system

• disorder/malfunction: heart attack/disease, blood clot, stroke, leukemia

regulation

• function: to control and coordinate the other life processes

• body system: nervous system and endocrine system

• disorder/malfunction: stroke (nervous), diabetes (endocrine)

gas exchange

• function: to take in oxygen and remove carbon dioxide

• body system: respiratory system

• disorder/malfunction: lung cancer, asthma

reproduction

• function: to add new members to a species

• body system: reproductive system

• disorder/malfunction: infertility, testicular cancer, prostate cancer, ovarian/cervical cancer

dynamic equilibrium and feedback mechanisms

• biochemical processes (enzyme-controlled reactions) in living things occur within a narrow range (“set point”) that are favorable for these cell activities

• living things are constantly exposed to changes in their external and internal environments so in order to maintain homeostasis, they must continually monitor and respond to these changes (stimuli)

• feedback mechanisms are used to detect changes inside the body and to take actions to return their systems to the normal range, or set point

• these controlled responses enable the organism to maintain homeostasis also known as dynamic equilibrium (failure to maintain homeostasis can result in disease, and possibly death of the organism)

examples of feedback mechanisms

• the changes in heart and respiratory rate in response to increased activity in muscle cells (exercise)

• the maintenance of blood sugar levels using insulin from the pancreas

• the changes in the stomates by guard cells in a leaf to regulate water loss and gas exchange in a plant

causes of disease

• pathogens

• genetic disorders

• organ malfunction

• poor nutrition

• cancer

• allergies

pathogens

• viruses, bacteria, fungi, and other parasites that infect plants and animals and interfere with normal life functions

• ex. strep throat, HIV/AIDS, pneumonia, colds, flus

genetic disorders

• diseases or malfunctions of the body resulting from changes in chromosome number, structure or gene mutations

• ex. Down’s Syndrome, cystic fibrosis, hemophilia

organ malfunction

• often the result of personal behaviors, some have a genetic component

• ex. heart attack, kidney disease, stroke, diabetes

poor nutrition

ex. diabetes, cardiovascular disease

cancer

• gene mutations in a cell can result in uncontrolled cell division (aka cancer)

• exposure of cells to certain toxic chemicals and radiation increases mutations and thus increases the chance of cancer

allergies

• when the body’s immune system responds inappropriately to a stimulus from the environment

• ex. pet dander, pollen or mold spores, bee stings, foods, etc.

the immune system

• protects against antigens associated with pathogens and foreign substances

antigen

• a protein on the surface of a cell that the body identifies as “self” (belonging to that individual) or “not self” (belonging to another organism or pathogens)

pathogens

• disease causing organisms

white blood cells

• are important part of the immune system

• includes phagocytes, lymphocytes, and antibodies

phagocytes

• eat the foreign invader by engulfing, and then digesting it

lymphocytes

• produce antibodies

antibodies

• proteins that are made for a specific antigen (and therefore a specific pathogen

• they attached to the antigen and help to destroy the invader

• the shape of the antibody matches the shape of the antigen

vaccinations (vaccines)

• use weakened bacteria or viruses to stimulate the immune system to react

• this reaction prepares the body to fight subsequent invasions by the same microbes, or pathogens

• vaccinations help to prevent the spread of disease

AIDS

• some viral diseases, like AIDS, damage the immune system, leaving the body unable to deal with multiple infectious agents and cancerous cells

• AIDS is caused by the HIV virus, which attacks T-cells, an important white blood cells in your immune system

• HIV (which causes AIDS) is contracted by unprotected sex and sharing needles

transplanted organs

• sometimes the immune system will attack transplanted organs

• recipients of transplanted organs are often given drugs to suppress the immune system (immunosuppressants) to help prevent this attack

• sometimes transplanted organs can be taken from close relatives to try to prevent organ (or tissue) rejection

steps for making a vaccination

1. obtain the pathogen

2. treat pathogen to kill or weaken it

3. inject altered pathogen (vaccine) into organism

4. body responds to antigens present by making antibodies and having white blood cells attack the invade

• some white blood cells specific for this pathogen remain in the body for a long time to continue the protection from future attacks by the pathogen