PowerPoint Presentation - Structure and Function in Living Systems
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Structure and
Function in Living
Systems
Chapter 8: Systems in Organisms
8.1: Systems help organisms meet their needs
8.2: Plants have several levels of organization
8.3 Animals have several levels of organization
8.4 Human health depends on a balance among systems
Human health depends on
a balance among systems
Levels of Organization
Fill in the sequential cluster diagram
epithelial, muscle,
nerve, connective
heart, skin, eyes;
respiratory, circulatory,
nervous, skeletal
How is the human body like a city?
The body’s systems work all the
time
Human body depends on processes that don’t stop
needs to:
Breathe
circulate blood
take in food, to digest it, and to eliminate waste materials
organ systems remain active during sleep
**working constantly to maintain the balance needed to
survive
Body systems maintain
homeostasis
Homeostasis: the ability of the body to
maintain internal conditions within normal
ranges
Conditions are in equilibrium = balanced
Small changes always occur internally and
externally
Body must work to regulate:
Body temperature
amount of sugar in blood
oxygen and carbon dioxide levels, and water
and salt balance in body fluids
Homeostasis: Negative Feedback
Homeostasis is often maintained by a negative feedback loop
Homeostasis: Body Temperature
Normal internal temperature is ~ 37°C (98–99°F).
homeostatic systems for temperature:
Integumentary, circulatory, muscular, respiratory,
and nervous
If much above or below 37°C:
The homeostatic systems are having trouble
maintaining your usual temperature
Active, or hot day body temperature may rise
Body sweats
Evaporation of sweat from skin cools body brings
temperature back down
Homeostasis: Ion Concentrations
Kidneys help keep body water volume constant
drink a lot of water kidneys release more water in urine
do not drink enough water kidneys make less urine
Why?
To maintain the proper concentrations of ions and other
substances in the blood
Concentration: amount of one substance that is dissolved in
another substance
The less water, the higher the concentration of dissolved
substances
The more water, the lower the concentration
Homeostasis: Ion Concentrations
Ion: an atom of an element that has gained or lost one or more
electrons – “charged” particles (+ or -)
important to many body processes:
movement of substances across cell membranes
sending of nerve impulses
Electrolytes: sodium, potassium, chloride, and calcium
skin tastes salty after sweating:
Sweat contains salts, ex: Sodium and chloride together
sports drinks contain salts (electrolytes!)
Electrolytes and salts, in ion form, are
substances that conduct electric
current.
Electrolytes in human body fluids
operate similarly to the currents
caused by electrolytes in batteries.
The positive and negative charges of
the ions cause them to move toward
concentrations of the opposite charge.
Electrolytes such as sodium,
potassium, calcium, magnesium,
and chloride ions in the human body
help fluids flow across cell membranes
and help nerve impulses travel.
Homeostasis: Oxygen and Carbon
Dioxide Concentrations
respiratory system and circulatory system
maintain a balance of oxygen and carbon
dioxide concentrations in the blood
These dissolved gases are carried by the
blood and delivered to and from the tissues in
plasma
Exercise: muscle cells use more oxygen and
give off more carbon dioxide than at rest
increased oxygen need increased
breathing rate and volume
heart pumps faster circulatory system
increases blood supply to the limbs
Resting: breathing is shallower, heart pumps
more slowly
Homeostasis: Other Nutrients
Liver
breaks down large food molecules—carbohydrates, fats, and
proteins—into nutrients
stores glucose, vitamins, and iron
produces bile (a fluid used in digestion)
breaks down alcohol, drugs, and other toxic chemicals
Filters, stores, and releases materials
Pancreas
Part of digestive and endocrine systems
helps maintain blood glucose levels
Some people with diabetes are
unable to make enough insulin
to regulate their blood sugar.
They often need to take
injections of insulin to keep their
blood sugar in a normal
homeostatic range.
The endocrine system helps
regulate body conditions
Controls the conditions in the body by making and
releasing hormones
Hormones: chemicals that are made in one organ, travel
through the blood, and produce an effect in target cells
Ex: insulin and glucagon produced in the pancreas
Ex: adrenaline makes your heart beat faster in exciting
situations
“rush of adrenaline”
Are often called chemical messengers
Target cells have special structures, called receptors, that
allow them to respond to the chemical messenger
Hormones and Glands
Glands: specialized - tissues main structures of the endocrine
system
Many glands in the body produce hormones circulatory system
Pineal Gland:
Tiny organ sizes of a pea
near the center of the brain
sensitive to light
produces a hormone essential to body rhythms
Ex: sleep
Plays a role in maintaining body temperatures, in reproducing, and
in aging
Hormones and Glands
Hypothalamus
connects the nervous and endocrine systems
Produces hormones that control the release of hormones
produced by the…
Pituitary Gland
base of the brain
director of the endocrine system
produces hormones that control growth, sexual
development, and the absorption of water into the blood by
the kidneys
Hormones and Glands
Thyroid Gland
releases hormones necessary for
Growth
Metabolism
regulation of calcium
Thymus Gland
helps the body fight disease by controlling the production of white
blood cells called T cells
Adrenal Glands
secrete about 30 different hormones
regulate carbohydrate, protein, and fat metabolism and water and
salt levels in the body
adrenaline –in response to stress
makes your heart beat faster
allows you to react quickly in dangerous or exciting situations
Hormones and Glands
Pancreas
part of both the digestive system and endocrine system
secretes insulin and glucagon
Regulate levels of glucose in the blood
Ovaries (female) and Testes (male)
secrete hormones that control sexual development
ovaries make more estrogen
testes make more testosterone
the different amounts of give males and females different
characteristics
What general area of the body are all the glands of the endocrine system in?
the center
What areas do the hormones produced in the glands generally affect?
all parts
How do the illustrations show the role of hormones as “chemical messengers”?
The glands are located throughout the body and are able to “deliver” hormones
wherever the body needs them
What are the glands of the endocrine system? pineal gland, hypothalamus,
pituitary gland, thyroid, thymus, adrenal glands, pancreas, ovaries, testes
Negative Feedback
Regulation of hormone levels
Adjust volume on a sound system
Friend says just right? stop changing the volume
You = control center
Friend = sensor
Feedback = information coming back to a control center from
a sensor that tells the control center what it needs to do to
maintain a level within an ideal range
signals to a gland that hormone levels are correct and no
more of the hormone is needed
Homeostasis may be disrupted
Signs of imbalance range from a mild cold, to dangerous overheating of
the body, to serious and even fatal diseases
Sneezing help defends the body from foreign substances
Pathogens (bacteria or virus) in the body signal the immune system
Symptoms begin to go away when homeostasis is restored
Exercising usually sweat
lose too much water dehydration
Signs of heat exhaustion: dehydration, dizziness, nausea, fainting, and a
dangerous drop in blood pressure
Heat stroke – possible if a person stops sweating temperature rise
Hypothermia - body temperature too low
Homeostasis
may be disrupted
hormone imbalances can cause serious diseases
Pancreas normally maintains glucose balance in your blood
by releasing insulin and glucagon as needed
Imbalance diabetes
failure of other organs, heart disease, blindness, and
kidney damage
Kidneys continually filter the blood, taking out waste products
Malfunction?
Dialysis: blood is circulated through an artificial kidney machine
that filters out the wastes (3 sessions/week!)