Week 7 Integumentary System

Week 7 Integumentary System

• The skin is the largest organ in the human body, making up approximately 16% of body weight. The skin consists of three layers: epidermis, dermis, and hypodermis.
• Epidermis: Composed of tightly packed epithelial cells (keratinocytes). It contains melanin for pigment production and keratin for skin strength. Five layers exist: stratum corneum (outermost layer of dead skin cells), stratum lucidum (present only in palms and soles), stratum granulosum (waterproof barrier layer), stratum spinosum, and stratum basale (deepest layer).
• Keratinocytes: The most abundant cells in the epidermis (90%) forming a protective barrier against environmental damage, such as UV radiation, pathogens, and water loss. They help with wound healing.
• Dermis: Two layers: papillary layer (highly vascularized areolar tissue; nourishes epidermis with capillaries, lymphatic vessels, and sensory neurons) and reticular layer (dense irregular connective tissue providing strength and flexibility; contains collagen and elastic fibers, sensory receptors, and blood vessels).
• Hypodermis: Separates skin from deeper structures. It contains adipose tissue providing insulation and cushioning, and stores energy reserves.
• Skin Color and Pigmentation: Skin color is determined by genetic programming, UV response, and melanin production.
• Medical conditions: Albinism, among others, affect skin pigment.
• Accessory Structures: Hair grows from hair follicles (comprising hair shaft, root, and bulb). Hair papillae have blood vessels and nerve endings. Nails are specialized epidermis on fingertips and toes; their continuous growth is from the nail root. Glands include sweat glands (eccrine for thermoregulation and apocrine in hairy areas) and sebaceous glands which produce sebum lubricating and waterproofing the skin.

Week 8 Digestive System

• Overview and Basic Functions: The digestive system processes food, extracts nutrients, and eliminates waste. It has five key stages: ingestion, digestion (mechanical and chemical), absorption, compaction, and defecation.
• Major Components: The alimentary canal and accessory digestive organs. Key organs of the alimentary canal are the mouth, pharynx, esophagus, stomach, small intestine, and large intestine which digests and absorbs nutrients. Accessory organs like teeth, tongue, salivary glands, liver, pancreas, and gallbladder assist in digestion.
• Alimentary Canal Wall Structure: Four main layers: mucosa (produces mucus), submucosa (blood vessels, lymphatics), muscularis (smooth muscle for digestion), and serosa/adventitia (outer covering).
• Major Digestive Organs: Stomach (upper left abdomen; function-food storage, breaking down food & moving it to small intestine; produces gastric juices and ghrelin for hunger regulation), liver (largest gland, regulates metabolism and produces bile), pancreas (produces digestive enzymes and hormones like insulin & glucagon), small intestine (duodenum, jejunum, ileum, major site for digestion completion and absorption), and large intestine (cecum, colon, rectum; water absorption).
• Digestion Processes: Carbohydrate digestion starts in the mouth with amylase and continues in the small intestine. Protein digestion starts in the stomach. Lipid digestion occurs mostly in the small intestine.
• Metabolism and Nutrition: Includes catabolic and anabolic reactions, affected by age, gender, and activity level. Balanced diet, including vitamins (fat-soluble and water-soluble), and water are essential.
• Health Considerations: Aging, diseases like peritonitis and colorectal cancer, and conditions like obesity and metabolic disorders impact digestive function.

Week 11 Lymphatic System

• Primary Functions: Fluid regulation by draining excess interstitial fluid, lymph formation (plasma leaking into tissue spaces), and disease prevention.
• Anatomical Components: Primary organs include bone marrow (immune cell production, B-cell maturation), and thymus (T-cell maturation). Secondary organs include lymph nodes (filtering debris & pathogens), spleen (blood filtration & immune response), tonsils, etc.
• Lymphatic Vessels: Transport network for lymph fluid.
• Immune System Components: Barrier defenses, innate immune response, and adaptive immune response.

Week 12 Urinary System

• Kidney Overview and Functions: Filters and cleanses blood, regulates fluid & electrolyte balance, synthesizes hormones, and helps regulate blood pressure.
• Anatomical Structure: The kidneys are paired organs located in the retroperitoneal space, protected by muscles and ribs. External anatomy includes kidney size, shape, and location. Internal anatomy includes renal cortex, medulla, calyces, and pelvis.
• Blood Flow: Kidneys receive 25% of cardiac output at rest. Major arteries include renal, segmental, interlobar, arcuate, and afferent arterioles.
• Nephron Structure and Function: Basic structure (glomerulus, Bowman's capsule, proximal convoluted tubule, loop of Henle, distal convoluted tubule, collecting ducts).
• Urine Formation Process: Three main steps (filtration, reabsorption, secretion). The formation of urine involves passive processes (driven by hydrostatic pressure).

Week 13 Sexual Systems

• Female Reproductive System: Includes external organs (vulva—mons pubis, labia majora, labia minora, and vestibule), internal organs (ovaries, uterus, vagina), and breast anatomy.
• Male Reproductive System: Includes testes (producing sperm and androgens) located in the scrotum. There's also the penis, sperm pathways, and accessory glands. These structures are crucial for reproduction.
• Hormones: Puberty, menstrual cycle (menses, proliferative, secretory), and spermatogenesis are influenced by hormones.
• Reproductive health: Factors like cervical cancer, birth control, and erectile dysfunction are aspects related to reproductive health. The reproductive system's response to mental and physical stimuli is discussed.

Explore the fascinating details of the integumentary system in this quiz. Learn about the different layers of skin, including the epidermis, dermis, and hypodermis, as well as the vital roles of keratinocytes and melanin. Test your knowledge on the structure and functions of this essential organ.