What are some ways… …your body protects you from invaders? …your body keeps you warm when you’re cold? …your body cools you down when you’re hot?

Your skin provides the 1 st line of defense against pathogens. When you’re cold, your hair stands up to trap in heat. When you’re hot, you sweat to cool yourself off.

The Integumentary System

Structures: – Skin – Hair – Nails Functions: – Protect against injury, infection, & fluid loss – Helps regulate body temperature (homeostasis)

Sebaceous Glands vs. Sweat Glands Sebaceous Glands: secrete sebum (oil) to lubricate Sweat Glands: secrete sweat to cool & excrete wastes

Which layer of skin must be penetrated for a cut to begin bleeding? Dermis – blood vessels are found in the dermis, so a cut needs to reach PAST the epidermis to the dermis. A.Hypodermis B.Epidermis C.Dermis D.Fat

Which glands keep your skin from drying out? A.Sebaceous B.Sweat C.Dermis D.Epidermis Sebaceous glands secrete oils to waterproof your skin. Sebaceous glands are found everywhere on your body except the palms of your hands & the soles of your feet!

Another way your skin protects you… Melanin is the pigment produced by skin cells & gives you your skin color. – People with darker skin produce more melanin, while people with fair skin have low levels of melanin. Melanin in the skin absorbs UV radiation, reducing the risk of cancer.

How does sun exposure affect melanin production? A.Increases melanin production B.Decreases melanin production C.Melanin levels will stay the same D.Depends on your skin color

Psoriasis Long term skin disease characterized by inflamed regions with scabs of dead skin – No cure, but symptoms can be managed with treatment Normal skin cells mature & replace dead skin cells every days. Psoriasis causes skin cells to mature in less than a week! Video to 1:20

Maintaining Homeostasis The integumentary system maintains homeostasis by protecting the body from outside agents & maintaining a stable body temperature. What other body system is closely associated with maintaining homeostasis?

The Excretory System

Removes excess or dangerous materials from the body – Homeostasis

How the Excretory System Maintains Homeostasis Filters the blood to remove waste (sugars, amino acids, salts, drugs) Maintains water & salt balance in the blood Maintains pH

Kidneys Blood in the body flows through the kidneys. The kidneys remove excess materials from the blood. This takes place in the nephrons of the kidneys!

Nephrons in the Kidneys

Blood filtration takes place in the glomerulus of the nephron. Blood from the renal artery enters the glomerulus. In the glomerulus, substances are removed from the blood & sent into the Bowman’s capsule. Filtered blood is then returned to the heart from the renal vein.

Vitamins – are they worth it? Video

Examples of Excess Materials Substances that diffuse out of the glomerulus: – Water – Salts – Glucose – Amino Acids – Vitamins (water soluble ones) Some substances are reabsorbed.

Urine The material that remains after reabsorption Urea + Salts + Water + Wastes = Urine

What is the correct pathway for urine to flow out of the human body? A.Kidney  Ureter  Bladder  Urethra B.Kidney  Bladder  Ureter  Urethra C.Bladder  Kidney  Ureter  Urethra D.Kidney  Urethra  Bladder  Ureter

Did you know?! It takes your kidneys about 45 minutes to filter your blood. Your blood passes through the kidneys about 300 times a day. The kidney has 1 million nephrons that filter the blood. Every day the kidney sends about 6 cups of urine to the bladder.

Kidney Stones Kidney stones are made of calcium, magnesium, & uric acid salts. Ultrasound waves break the stone into smaller fragments that can pass out of the body. This kidney stone is 8 mm in diameter! OUCH! Video to 2:15

Dialysis Use of a machine to filter the blood when kidney failure occurs – On average, treatment lasts 4 hours & is needed 3 times per week.

Before you leave, answer the following question on a sheet of paper (share!): How do the integumentary & excretory systems play a role in homeostasis? Give an example of each!