Bio Unit 8

Circulatory system:

This body system moves nutrients and oxygen to the cells of the body using pressure and diffusion. Includes capillary beds.

Digestive system:

This body system uses mechanical breakdown and enzymes to provide the cells of the body with the necessary monosaccharides, lipids, and amino acids.  

Endocrine system:

This body system sends “slow” signals throughout the body using hormones. Includes the pituitary gland.

Integumentary system:

This body system protects and insulates the body and is involved in the production of Vitamin D.

Lymphatic system:

• This body system is involved in the immune system's fight against infection and moves fluids throughout the body. Includes the spleen and tonsils. 

Muscular system:

This body system moves the body, maintains posture and generates heat.   

Nervous system:

This body system sends “fast” messages throughout the body. Includes neurons. 

Reproductive system:

This body system facilitates the fusion of two gametes.

Respiratory system:

This body moves oxygen from the air to the bloodstream and removes carbon dioxide from the body. 

Skeletal system:

• This body system protects internal organs, stores minerals, and provides support. 

Urinary system:

This body system cleans the blood and removes wastes from the body. Includes the kidneys.

What is homeostasis?

Processes that maintain a stable internal environment in cells/bodies.

Why are negative feedback mechanisms used by the body to maintain homeostasis? 

Negative feedback mechanisms occur when the body senses it has moved away from set point (homeostasis target) and the body’s response returns it to set point. 

Positive feedback is rarely used in the human body. What is one example of when a positive feedback mechanism is used? 

• Uterine contractions during childbirth are an example of positive feedback. 

What do glands produce and secrete?

Hormones

What is the purpose of hormones? What are the two categories of hormones?

• Hormones allow cells to communicate with one another. 

• Lipid-based (steroid) hormones, like estrogen, diffuse into target cells. 

• Protein-based hormones, like ADH, are received by membrane receptors of target cells. 

1. True or false. Hormones are often used for communication between sensory cells and response cells for negative feedback. 

True

FSH:

•  Gonads; tells testes and ovaries to mature gametes

LH

Gonads; causes ovulation in women.

Estrogen;

• Many cells; tells the uterine lining to thicken; tells bone cells to increase density. 

Progesterone

; Many cells; tells the uterine lining to thicken

Melatonin:

• Some brain cells; regulates day/night cycles. Tired at night. Alert in the morning. 

ADH:

• kidneys: counteracts dehydration by preventing the water in blood from becoming urine. 

Epinephrine;

Many cells of the body; release sugar into the bloodstream, increasing heart and respiration rate.

Insulin

•  Cell of the body; tells cells to open their glucose channels to lower blood sugar levels. 

What are all of the organs, in order, that food passes through the digestive system as it is broken down and absorbed?

• Mouth (food→ bolus)

• Esophagus

• Stomach (bolus →chyme)

• Small intestine 

• Large intestine (chyme → feces)

  1. Rectum 

  2. Anus

Chemical digestion:

1. Enzymes 

2. Acids 

3. Bile (emulsifies fats) 

Mechanical digestion:

1. Chewing

2. Peristalsis 

3. Churning

Where does both chemical and mechanical digestion start?

• The mouth (chemical=salivary amylase; mechanical=chewing)

What occurs in the stomach?

The partially digested food spends a few hours in the chamber while acids and pepsin enzymes break down the bolus into chyme.

Pancreas:

• makes and secretes many digestive enzymes into the small intestine. 

Liver:

Makes bile

Gallbladder:

• stores bile and secretes it into the bile duct which moves the bile to the small intestine. 

1. Most absorption of nutrients occurs in the small intestine. What adaptations do villi and microvilli have that allows for more absorption of nutrients? 

• Folds of membrane with additional folds of membrane. This greatly increases the surface area and the amount of transport proteins that are exposed to the small intestine (so resorption happens faster and completely)

What occurs in the large intestine?

• The undigested food has its water removed and moved back into the bloodstream. 

• Some vitamins are also absorbed by the bloodstream. 

• At the end of the large intestine (rectum) the feces formation occurs. 

1. What type of chemical reaction is catalyzed by all of the digestive system enzymes (like amylases, lipases, proteases)?  

• Hydrolysis

Kidney:

filters the blood

Renal artery:

1. receives the blood supply (“dirty” blood) from the heart/body.  

Renal vein:

1. carries blood (“cleaned” blood) out of the kidney and back to the heart. 

Nephron:

1. millions of these are found in kidneys. It is where some materials are removed from the blood and placed into urine. 

Ureter

 carries the urine made in the nephrons to the bladder.

Bladder

stores urine.

Urethra:

• carries urine from the bladder and out the body. 

What do the nephrons in a kidney do?

• It filters blood. First filtrate is taken from the blood. 

• Then sugars, amino acids and some water is reabsorbed into the blood.

1. What is one way in which the urinary system is involved in the maintenance of homeostasis? 

• There is a set point of the optimal amount of water in the blood. 

What does the circulatory system move around the body in blood?

• Water

• Sugars

• Amino acids

• Vitamins and minerals

• Hormones

• Red blood cells 

  1. Oxygen (hemoglobin proteins in RBC binds to oxygen)

  2. Carbon dioxide

• White blood cells (fight infection)

• Platelets (blood clotting factor)

1. The circulatory system is a 1 way path. What prevents the backflow of blood in the heart and veins? What about arteries? 

• Blood moves from the heart (left ventricle to aorta) to arteries to capillary beds to veins and back to the heart (vena cava into right atrium)

• The heart and veins use valves to prevent backflow

• The arteries use blood pressure to move blood away from the heart.

What are the two functions of the respiratory system?

• Move oxygen from the air to the bloodstream

• Move carbon dioxide out of the body. 

Epiglottis:

• Flap in the throat that prevents food from entering the respiratory system. 

Larynx:

Allow air to travel to the trachea. Also contains the voice box.

Trachea:

Allows air to travel to the lungs.

Bronchi:

Branch at base of trachea that directs air to each

Alveoli in lungs:

• he air sacs. Millions of alveoli are found in the lungs and this is where gas exchange occurs. O2 from air to blood and CO2 from blood to air. 

Diaphragm:

Muscle that is inferior to the lungs and superior to the stomach/intestines. When the diaphragm contracts it draws air into the lungs. When it relaxes air is pushed out of the lungs and through the nose.