1. Human Systems and Homeostasis
Biology - Chapter 28

2. KEY CONCEPT The human body has five levels of organization.

3. Specialized cells develop from a single zygote.
Organisms are made up of specialized cells.
red blood cell
nerve cell

4. Zygotes first divide into embryonic stem cells.
Stem cells develop in two stages.
determination, or committing to become one cell type
differentiation, or acquiring specialized structures and functions

5. Specialized cells function together in tissues, organs, organ systems, & the whole organism.
Specialized cells perform specific tasks.
Tissues are groups of similar cells working together.
epithelial tissue
connective tissue
muscle tissue
nervous tissue
cell
tissue

6. Organs are different tissues working together.
Organ systems are two or more organs working together.
Organism is all organ systems working together.
ORGANS
ORGAN SYSTEM
ORGANISM

7. There are 11 major organ systems in the human body.

8. Organ Trail Assignment
Adrenal Glands Hypothalamus Rectum
Anus Kidneys Salivary Glands
Appendix Large Intestine Skeletal Muscles
Bladder Skin Larynx (voice box)
Bones Liver Small Intestine
Brain Lungs Spinal Cord
Bronchi Spleen Lymph Nodes
Ears Mouth Stomach
Esophagus Nose Thymus Gland
Eyes Trachea Pancreas
Gall Bladder Thyroid Parathyroid Glands
Genitals—Female/Male Ueters Pituitary Gland
Heart Urethra Prostate

9. Conditions within the body must remain within a narrow range.
Homeostasis involves keeping the internal environment within set ranges.

10. Control systems help maintain homeostasis.
sensors gather data
control center receives data, sends messages
communication system delivers messages to target organs, tissues
targets respond to change
pore
sweat
glands
hair
follicle
muscle
goose
bump

11. Negative feedback loops are necessary for homeostasis.
Feedback compares current conditions to set ranges.
Negative feedback counteracts change.
Negative Feedback Loop
O2 / CO2 level returns to normal
Holding breath, CO2 levels rise,
Control system forces exhale, inhale

12. Negative Feedback loop Modeling pg 861
Problem: how does a negative feedback loop work?
Procedure: balance a hardcover book on your head; walk 3 meters forward and backward—once with eyes open, once with eyes closed.
Questions:
1)Describe the negative feedback loop that helped keep the book balanced on your head. How did closing your eyes affect your ability to balance the book?
2)Think of another example of a negative feedback loop that you might observe in your everyday life. Explain how you think this loop works.

13. Positive feedback increases change.
Torn vessel stimulates release of clotting factors
platelets
fibrin
white blood cell
red blood cell
blood vessel
clot
growth hormones stimulate cell division

14. Each organ system affects other organ systems.
An organ system must do a specific job.
Organ systems must also work together to keep the organism healthy.

15. Organ systems must also work together to keep the organism healthy.
Organ systems work together to produce Vitamin D.
Thermoregulation maintains a steady body temperature. 1 2 3 4
Skin absorbs UV light
Liver produces inactive vitamin D
Kidneys produce active vitamin D
Active vitamin D used in bones
UV light

16. A disruption of homeostasis can be harmful.
Homeostasis can be disrupted for several reasons.
sensors fail
targets do not receive messages
injury
illness

17. Short-term disruption usually causes little or no harm.
Long-term disruptions can cause more damage.
Diabetes is a serious long-term disruption of homeostasis. 1 2 3 4
Pancreas cells attacked;insulin declines
Blood glucose levels rise,
Body burns fat; blood more acidic,
Cells impaired; all organs damaged.
pancreas
fats
kidneys