Homeostasis and Human Body Systems. Imagine you are playing softball on a warm summer day. Write down two ways that your body would adjust to keep you cool and to keep your muscles working. Key Ideas. How does a change in the external environment affect an organism?
Homeostasis and Human Body Systems
Imagine you are playing softball on a warm summer day. Write down two ways that your body would adjust to keep you cool and to keep your muscles working.
Decrease room temperature
Increase room temperature
Increase room temperature
Stomata (singular: stoma), are pore-like openings in the underside of the leaf that allow carbondioxide and oxygen to diffuse into and out of the leaf. Each stoma consist of: two guardcells, the specialized cells in the epidermis that control the opening and closing of stomata by responding to changes in water pressure.
Human Body Systems
Alternately bend and straighten your arms or legs while feeling the muscles in the front and the back.
Write down what you feel when the limb is straightened and what you feel when the limb is bent.
Axial skeleton – supports the central axis of the body; skull, vertebral column, and rib cageAppendicular skeleton – bones of arms and legsWhat do you think is a better model of a bone, a stick of chalk or a sponge?The chalk may look more like a bone but the sponge shows what the structure actually looks like inside.
Blood vessels and nerves
Bone is surrounded by a tough layer of connective tissue
Network of tubes that contain blood vessels and nerves.
What do you think might happen to the bones that are not exposed to force, such as the bones of astronauts in zero gravity?
Slightly Movable Joints
Freely Movable Joints
What are the three types of muscle?
Neuron – cells that transmit impulses
What is an impulse?
Cell body – largest part of a neuron; contains the nucleus and most of the cytoplasmDendrites – short, branched extensions spreading out from the cell body; receive impulsesAxon – long thin fiber that carries impulses away from the cell bodyAxon terminal – end of an axon that sends impulses to another neuron
What are the 5 types of sensory receptors?
Also involved with reflexes ex) you touch a hot stove – your hand pulls back before you sense the pain – Reflex Arc - this information goes from hand to spine back to hand again; it never reaches the brain because it would take too long
Key Concept Questions:
What are the different classes of drugs that directly affect the central nervous system?
What is the effect of alcohol on the body?
Stimulants – increase the actions regulated by the nervous system
Depressants – decrease the rate of functions regulated by the brain
How might someone behave if they have taken a depressant?
They might be slow moving and sleepy and speak with a slur
Cocaine – comes from the leaves of the cocoa plant-causes sudden releasein the brain of neurotransmitter called dopamine-causes ADDICTION– an uncontrollable craving for more of the drug-dopamine is normally released when a basic need has been fulfilled (thirst, hunger)-cocaine tricks the brain into releasing large amounts of dopamine and produces intense feelings of pleasure and satisfaction-when the drug wears off the level of dopamine drops sharply and the user feels sad and depressed-strong psychological dependence-powerful stimulant – increases heart rate, and blood pressure-some first time users can have a heart attack and dieCrack is very potent form of cocaine; highly addictive after one use
Opiates – comes from flower called poppy ex) morphine, codeine, heroin
Hallucinogens – drugs that cause hallucinations
Ecstasy - both a hallucinogenic and a stimulant drug.
Marijuana– comes from cannabis plant
Alcohol – one of the most dangerous and abused drugs
DRUGABUSE – using a drug in any way that most doctors could not approvePsychological dependence – mental craving, or need for the drugPhysical dependence – the body cannot function without a constant supply of the drug
Which type of addiction do you think would be harder to break – psychological or physical?
The endocrine system is made up of glands that release their products into the bloodstream. These products broadcast messages throughout the body.
The chemicals that “broadcast” messages from the endocrine system are called hormones.
specific body condition
hormone carried by blood
The thyroid gland has the major role in regulating the body’s metabolism
Hormones produced by the thyroid gland and the parathyroid glands maintain the level of calcium in the blood
The adrenal glands help the body prepare for and deal with stress
Insulin and glucagon released from the pancreas help to keep the level of glucose in the blood stable
When the pancreas produces too little insulin, a condition known as diabetes mellitus occurs.
In diabetes mellitus, the amount of glucose in the blood may rise so high that the kidneys actually excrete glucose in the urine
Very high blood glucose levels can damage many organs and tissues, including the coronary arteries.
Endocrine System Control
body cells takeup sugar from blood
blood sugar level
Teeth – mechanical digestion; chewing the foodSaliva – contains AMYLASE – enzyme that breaks chemical bonds between the sugar monomers in starchesEsophagus – food tube that goes from mouth to stomach
PANCREAS – sits just below the stomach
Jejunum and ileum – 2nd and 3rd parts of the small intestine
Large intestine – removes water from undigested material that is left
undigested material left in the colon
compounds that the body can use, such
as vitamin K.
remains after the water has been
removed passes through the rectum
and is eliminated from the body.
What are the structures of the respiratory system?
Your heart can beat faster or more slowly, depending on your body’s need for oxygen-rich blood.
In times of stress, does the heart beat faster or slower?
It beats faster
Write a short explanation of how you think a thermostat on a furnace helps to keep the room temperature at a comfortable level.
Answer the following question:
How does the human body act like a thermostat?