HBS

Label the structures of the eye on a picture, from memory:

1. Cornea

2. Pupil

3. Iris

4. Lens

5. Retina

6. Optic nerve

7. Sclera

8. Macula

9. Vitreous humor

What are the two parts of the eye that focus light?

The cornea and the lens are the two parts of the eye that focus light.

Describe the function of each major component of the eye:

1. Cornea: The clear, dome-shaped surface that covers the front of the eye and helps to focus incoming light.

2. Pupil: The opening in the center of the iris that regulates the amount of light entering the eye.

3. Iris: The colored part of the eye that controls the size of the pupil.

4. Lens: The transparent structure behind the iris that further focuses light onto the retina.

5. Retina: The light-sensitive layer at the back of the eye that converts light into electrical signals.

6. Optic nerve: The nerve that transmits visual information from the retina to the brain.

7. Sclera: The white, outer layer of the eye that provides structure and protection.

8. Macula: The central part of the retina responsible for sharp, detailed vision.

9. Vitreous humor: The clear gel that fills the space between the lens and the retina, helping to maintain the eye's shape.

What is conjunctivitis and what is the cause?

Conjunctivitis, also known as pink eye, is an inflammation or infection of the conjunctiva, the transparent membrane that lines the eyelid and covers the white part of the eyeball. It can be caused by bacterial or viral infections, allergens, or irritants.

Describe the cause and symptoms of the following eye diseases:

1. Conjunctivitis:

   - Cause: Bacterial or viral infections, allergens, or irritants.

   - Symptoms: Redness, itching, tearing, discharge, and a gritty feeling in the eye.

2. Glaucoma:

   - Cause: Increased pressure in the eye that damages the optic nerve.

   - Symptoms: Gradual loss of peripheral vision, tunnel vision, and in advanced stages, loss of central vision.

3. Macular Degeneration:

   - Cause: Deterioration of the macula, often age-related.

   - Symptoms: Blurred or reduced central vision, difficulty recognizing faces, and dark or empty areas in the center of vision.

4. Myopia (Nearsightedness):

   - Cause: The eye is too long or the cornea is too curved, causing light to focus in front of the retina.

   - Symptoms: Difficulty seeing distant objects clearly.

5. Hyperopia (Farsightedness):

   - Cause: The eye is too short or the cornea is too flat, causing light to focus behind the retina.

   - Symptoms: Difficulty seeing close objects clearly.

6. Cataracts:

   - Cause: Clouding of the eye's lens, often age-related.

   - Symptoms: Blurred vision, faded colors, glare, and difficulty seeing at night.

7. Astigmatism:

   - Cause: Irregular curvature of the cornea or lens.

   - Symptoms: Blurred or distorted vision at all distances.

8. Subconjunctival hemorrhage:

   - Cause: Broken blood vessels under the conjunctiva, often due to minor trauma or strain.

   - Symptoms: A bright red patch on the white of the eye, usually without pain or vision changes.

1. Organs of the Urinary System:

   The main organs of the urinary system include:

   - Kidneys

   - Ureters

   - Bladder

   - Urethra

2. Functions of the Urinary System Other Than Urine Formation:

   - Regulation of blood volume and blood pressure

   - Regulation of electrolyte balance

   - Regulation of acid-base balance

   - Removal of metabolic waste products and toxins

   - Production of hormones like erythropoietin and renin

3. Nephron:

   A nephron is the functional unit of the kidney responsible for filtering blood and forming urine. Each kidney contains about a million nephrons. Nephrons are located in both the cortex and medulla of the kidney.

4. Labeling Parts of Kidney and Nephron:

   - Cortex: The outer layer of the kidney.

   - Medulla: The inner region of the kidney.

   - Pyramids: Triangular sections within the medulla.

   - Capsule: The outer covering of the kidney.

   - Collecting Duct: Tubes that collect urine from nephrons and move it to the renal pelvis.

   - Loop of Henle: A U-shaped part of the nephron that concentrates urine.

   - Proximal Convoluted Tubule: The part of the nephron where reabsorption of water, ions, and nutrients occurs.

   - Distal Convoluted Tubule: The part of the nephron involved in the secretion and reabsorption of ions.

   - Glomerulus: A network of capillaries where blood filtration begins.

   - Bowman's Capsule: A cup-like structure surrounding the glomerulus.

   - Efferent Arteriole: Carries blood away from the glomerulus.

   - Afferent Arteriole: Carries blood to the glomerulus.

5. Difference Between Filtration, Secretion, and Reabsorption:

   - Filtration: The process by which blood plasma is filtered through the glomerulus into Bowman's capsule. This occurs in the glomerulus.

   - Secretion: The process by which substances are moved from the blood into the nephron tubule. This occurs mainly in the distal convoluted tubule and collecting duct.

   - Reabsorption: The process by which water and essential solutes are reabsorbed from the nephron tubule back into the blood. This occurs in the proximal convoluted tubule, loop of Henle, distal convoluted tubule, and collecting duct.