1. What are all the systems? How do they work together?
Human Body Systems
What are all the systems?
How do they work together?

2. Levels of Organization
Cells -> tissue -> organs -> organ systems -> complete organism
Goes from smallest unit (cell) to largest unit (complete organism)
Example: cell -> stomach tissue -> stomach -> digestive system -> mouse

3. Each organ system has a specific job to carry out in order to keep an organism alive.
Digestive – Mouth, esophagus, stomach, intestines, anus; functions to breaks down large food molecules into smaller ones that can be absorbed by the body.
Endocrine- works with the brain and reproductive organs to keep a steady balance of HORMONES in your system
Integumentary- Skin, used to protect the body from invasion by bacteria; Helps maintain homeostasis (internal wellness)
Reproductive- Used to produce offspring; Male and female systems different!

4. Respiratory – Lungs, used to breathe (Inhale Oxygen and exhale Carbon Dioxide)
Excretory – Kidneys, filter liquid nitrogenous waste products
Nervous – brain/spinal cord; sensory systems; detects both Internal and External stimuli

5. Circulatory – heart; circulates blood throughout the body to carry oxygen to cells
Muscular – muscles; moves the bones and is directly involved most body systems (cardiac muscles, smooth organ muscles)
Immune – lymph nodes; helps to fight against infections and foreign bodies that enter the body
Skeletal – bones; support system and contains all the bones

6. Digestive System Organs
Esophagus-smooth muscle contractions “squeeze” food down to the stomach
Stomach- gastric juices and enzymes break down (digest) large food chunks
Small Intestine- digestion finalized; microvilli begin absorbing nutrients through inner lining and into blood stream
Large Intestine- last of nutrients absorbed, main place for water absorption!

7. Villi and Microvilli of the Intestines!!!
Fingerlike projections that coat the inside of our intestines.
Increase overall surface area so that we can get maximum absorption of nutrients into our blood stream!
Connect to capillaries (small blood vessels that feed into major veins and arteries!)

8. Digestive System “Accessory” Organs
Liver- filters nutrients and vitamins out of your blood; also produces bile (a green digestive juice)
Gall bladder- stores bile for later use; looks like a green balloon under the liver!
Pancreas- makes digestive juices for breaking down fat/ protein; also makes insulin (hormone that regulates blood sugar levels)
Appendix- no apparent function for us; some herbivores use it to break down grass/tough plants.

9. Circulatory system
Uses red blood cells to deliver oxygen to cells for cellular respiration!
Also, food molecules absorbed by the intestines travel with blood cells; passed on to other cells in the body.
Traveling route for platelets (forms clots) and white blood cells (fight off foreign invaders!)

10. Respiratory/Cardiovascular System
Trachea- tube of cartilage (wind pipe) that runs towards the lungs
Lungs- extract any oxygen from air and transfer it to your blood.
Veins/Arteries/Blood vessels- carry blood to all areas of the body
Heart- acts as a pump to circulate blood; muscular

11. Excretory System AKA Urinary System!!!
Kidneys- use nephrons to filter wastes and toxins from our blood and form urine
Ureters- tubes that carry urine to bladder
Bladder- stores urine until released by urination
Urethra- carries urine out of the body (exit!)

12. Reproductive System Testes- produce sperm Ovaries- produce eggs
Uterus- (womb) where an embryo develops into a baby
Penis and Vagina-sexual organs involved in fertilization
Number of hormones involved from the endocrine system (testosterone, estrogen, etc.)
Needed for survival of the species, but not the individual!

13. Nervous System
Neurons- brain cells; look very branched; send electrical impulses!
Nerves- long connections of neurons; run all over the body
Spinal Cord- main nerve that runs from your brain
Brain- controls actions of the body; all other body systems controlled by this organ!

14. Endocrine System
Glands secrete hormones (chemical messengers) when triggered by the nervous system OR other hormones.
Responding to different internal/external stimulus!
Hormones affect the inner actions of the body (heart rate, hair growth, sweating, pupil dilation, etc.)

15. Maintaining Homeostasis
Both the nervous system and endocrine system help maintain a healthy, stable internal environment (aka “homeostasis”)
Sensory organs and nervous system recognize changes, which usually trigger internal endocrine responses OR behavioral responses!
EX: sweating, shivering, vomiting, tears, etc.

16. Integumentary System Skin, hair, sweat glands, fat tissue all included
Functions to protect you from external environment and respond to feeling a stimulus!

17. Muscular/ Skeletal System
Bones- provide support
Muscles- connect to nerves and move the body and bones
Connective tissue- tendons, ligaments, cartilage, joints, etc.
Smooth muscle meant to contract inside organs
Cardiac muscles in heart

18. Immune System Specialized White Blood Cells (WBC)
Produced in bone marrow
B cells- recognize invaders and produce antibodies
T cells (killers)- target and destroy invaders using endocytosis

19. Match the System to the organs involved!
Endocrine
Excretory
Integumentary
Immune
Digestive
Circulatory
Respiratory
Nervous
Skin, hair, nails
Heart, arteries, capillaries, veins, blood
White blood cells, such as T-cells and B-cells
Glands, hormones
Lungs, larynx, trachea, bronchioles
Kidneys, ureters, bladder
Neurons, brain
Stomach, intestines, esophagus