Lecture on Nitrogenous Waste and Urinary System

Overview of Nitrogenous Waste

Product of Metabolism: Urea is the primary product discussed.
Carbon Dioxide and Water: Result from glucose breakdown during respiration.
Excess Salts and Ions: Excreted by kidneys, come from various metabolic processes.

Proteins: Main source of nitrogenous waste.
Deamination: Process of removing an amine group from proteins by the liver.
- Hormones and proteins in blood are broken down, and the amine group (NH2) is removed.
Ammonia: Highly toxic, some organisms convert nitrogenous waste to ammonia.
Uric Acid: Solid form, can cause gout if built up in human blood. Used by birds and insects to conserve water.
Urea: Preferred in humans; less toxic than ammonia, soluble and easy to transport in blood.

Chemical Breakdown: Urea can decompose into ammonia with warmth, causing chemical burns on babies’ skin, known as diaper rash.
Ammonia: Harmful to skin, can cause blisters and sores, leading to fungal infections.

Lungs: Expel carbon dioxide and water vapor; alcohol can also be expelled via breath.
Skin (Sweat): Excretes water, salts, and slight urea.
Liver: Filters out dead cells, excess proteins, toxins, but does not excrete outside.
Kidneys: Produce urine, filter blood to remove urea and other waste products.

Position and Anatomy: Retroperitoneal; right kidney sits lower due to liver displacement.
Nephron: Functional unit of the kidney, responsible for filtering blood.
- Glomerular Filtration: Blood is filtered in the glomerulus.
- Tubular Reabsorption: Returns useful substances and water to blood.
- Tubular Secretion: Removes additional unwanted substances.
- Collection of Urine: Final urine is collected in the collecting ducts.

Juxtaglomerular Cells: Monitor blood pressure; release renin when blood pressure is low.
Renin-Angiotensin System: Increases blood pressure and volume, prompts water reabsorption.

Structure: Composed of serosa (top), adventitia (sides), detrusor muscle, and mucosa with rugae.
Function: Stores urine, stretches via detrusor muscle and transitional epithelium.
Trigone: Smooth area at the bladder base, aids in the smooth flow of urine.

Sphincters:
- Internal Urethral Sphincter: Involuntary control.
- External Urethral Sphincter: Voluntary control.
Process: Bladder stretches, sends signal to brain, relaxes internal sphincter; voluntary control maintains until urination.

Study Focus: Male and female reproductive systems with structural and functional details.
Development Processes: Fertilization, early embryonic development, implantation, and fetal development.

Note: Ensure understanding of kidney function, hormone regulation, and urinary system anatomy for exams.