Functions of the Human Body Exam Review PDF

Week 7 Integumentary System Structure of the Skin The skin is the largest organ of the human body, comprising approximately 16% of body weight. It consists of three main layers: Epidermis - Made of closely packed epithelial cells (Keratinocytes) - Contains melanin (pigment production) - Contains k...

Week 7 Integumentary System Structure of the Skin The skin is the largest organ of the human body, comprising approximately 16% of body weight. It consists of three main layers: Epidermis - Made of closely packed epithelial cells (Keratinocytes) - Contains melanin (pigment production) - Contains keratin (skin rigidity) - Consists of five layers: 1. Stratum corneum (dead skin cells) 2. Stratum lucidum (only in palms and soles) 3. Stratum granulosum (waterproof barrier) 4. Stratum spinosum (8-10 layers) 5. Stratum basale (base layer) Keratinocytes - Primary cell type (90% of epidermal cells) - Forms barrier against environmental damage - Protects against heat, UV radiation, water loss, pathogens - Aids in wound healing Dermis Two main layers: 1. Papillary Layer - Highly vascularized areolar tissue - Contains capillaries, lymphatic vessels, sensory neurons - Nourishes epidermis 2. Reticular Layer - Dense irregular connective tissue - Contains collagen and elastic fibers - Provides strength and flexibility - Houses sensory receptors and blood vessels Hypodermis - Separates skin from deeper structures - Contains adipose tissue - Provides insulation and cushioning - Stores energy reserves Skin Color and Pigmentation Factors affecting skin color: - Genetic programming - UV response - Melanin production - Carotene (orange-yellow pigment) - Medical conditions like albinism Accessory Structures Hair - Keratin filament growing from hair follicles - Components include hair shaft, root, and bulb - Hair papilla contains blood vessels and nerve endings Nails - Specialized epidermis at fingertips and toes - Nail bed forms foundation - Continuous growth from nail root - Pink appearance due to rich blood supply Glands 1. Sweat Glands (Sudoriferous) - Eccrine: thermoregulation - Apocrine: found in hairy areas 2. Sebaceous Glands - Produce sebum - Lubricate and waterproof skin - Have antibacterial properties Functions of Skin - Protection - Thermoregulation - Sensory reception - Immunity - Hormone production - Fluid and electrolyte balance - Absorption - Excretion - Secretion Sensory Systems Gustation (Taste) - Detects basic tastes: sweet, salty, sour, bitter - Located in taste buds on tongue - Uses stratified squamous epithelium Olfaction (Smell) - Olfactory receptor neurons in nasal cavity - Processes chemical stimuli - Connected to temporal lobe and limbic system Audition (Hearing) Structure of the ear: - Outer ear: auricle, auditory canal - Middle ear: malleus, incus, stapes - Inner ear: cochlea, vestibule - Eustachian tube for pressure equalization Vision Eye anatomy: - Located in bony orbits - Protected by eyelids and eyelashes - Controlled by six extraocular muscles - Light pathway: cornea → aqueous humor → pupil → lens → vitreous humor → retina → optic nerve Vestibular System (Balance) - Located in inner ear - Uses mechanoreceptors - Includes utricle and saccule - Senses head position and movement - Uses fluid movement for balance detection Week 8. DIGESTIVE SYSTEM Overview and Basic Functions The digestive system processes food, extracts nutrients, and eliminates waste through five key stages: 1. Ingestion 2. Digestion (mechanical and chemical) 3. Absorption 4. Compaction 5. Defecation Major Components Alimentary Canal (GI Tract) - Measures approximately 7.62 meters during life - Main organs: mouth, pharynx, esophagus, stomach, small intestine, large intestine - Primary function: digestion and nutrient absorption Accessory Digestive Organs - Includes: teeth, tongue, salivary glands, liver, pancreas, gallbladder - Support food breakdown and digestion - Connect to gut via ducts Alimentary Canal Wall Structure Four main layers: 1. Mucosa - Produces mucus - Contains epithelium in contact with food - Houses immune tissue (MALT) 2. Submucosa - Contains blood vessels and lymphatics  - Houses submucosal plexus - Contains digestive glands 3. Muscularis - Inner circular and outer longitudinal muscle layers - Promotes mechanical digestion - Controls food movement 4. Serosa - Outer covering in abdominal cavity - Replaced by adventitia in some regions Major Digestive Organs Stomach - Located in upper left abdomen - Functions: - Food storage - Breaking down food - Moving food to small intestine - Produces gastric juices for digestion - Contains ghrelin for hunger regulation Liver - Largest gland in body - Weighs 3 pounds in adults - Functions: - Produces bile - Metabolic regulation - Detoxification - Contains hepatocytes (80% of volume) Pancreas - Both exocrine and endocrine functions - Produces: - Digestive enzymes - Hormones (insulin, glucagon) - Located behind stomach - Connected to duodenum Small Intestine - Divided into duodenum, jejunum, and ileum - Main site for digestion completion and absorption - Features increased surface area through: - Circular folds - Villi - Microvilli Large Intestine - Components: cecum, colon, rectum - Functions: - Water absorption  - Feces formation - Bacterial synthesis of vitamins - Waste elimination Digestion Processes Carbohydrate Digestion - Begins in mouth with salivary amylase - Continues in small intestine - Breaks down complex carbs to simple sugars Protein Digestion - Starts in stomach with pepsin - Completed in small intestine - Results in amino acids Lipid Digestion - Mainly occurs in small intestine - Requires bile from liver - Breaks down fats into fatty acids and monoglycerides Metabolism and Nutrition Basic Metabolism - Includes anabolic and catabolic reactions - Affected by age, gender, activity level - Requires oxygen for cellular respiration Nutritional Considerations - Balanced diet following Canada's Food Guide - Importance of vitamins (fat-soluble and water-soluble) - Water as essential nutrient - Obesity concerns and health impacts Health Considerations - Aging affects digestive system function - Common disorders include: - Peritonitis - Colorectal cancer - Obesity-related conditions - Metabolic disorders can affect nutrient processing Week 10 Endocrine System Overview The endocrine system maintains homeostasis through hormones - chemicals that originate in tissues and organs and affect other tissue/organs. These hormones vary from simple amino acids to complex combinations of lipids, proteins, and carbohydrates. The system works alongside the nervous system to provide communication pathways in the body. Hormone Types and Structure Hormones are categorized into three major groups: - Amino acid derivatives (amines) - Peptides - Steroids Communication Pathways Five major pathways facilitate hormone movement: 1. Paracrine pathway 2. Autocrine pathway 3. Endocrine pathway 4. Synaptic pathway 5. Neuroendocrine pathways Hormone Effects and Interactions Types of Effects - Permissive Effect: One hormone enables another to act - Synergistic Effect: Two hormones produce an amplified response - Antagonistic Effect: Two hormones have opposing effects Feedback Mechanisms 1. Positive Feedback Loop - Continues until interrupted - Example: Oxytocin during childbirth 2. Negative Feedback Loop - Regulates hormone levels within a narrow range - Example: ADH regulation of fluid levels Major Endocrine Glands and Functions Hypothalamus-Pituitary Complex - Acts as command center of the endocrine system - Produces releasing and inhibitory hormones - Controls other endocrine glands Thyroid Gland - Produces T3 and T4 hormones - Regulates basal metabolic rate - Influences body temperature - Regulated by TSH Parathyroid Glands - Usually four glands embedded in thyroid - Produces PTH for calcium regulation - Affects bones, intestines, and kidneys Adrenal Glands - Located atop kidneys - Consists of cortex and medulla - Responds to physical and psychological stress - Produces stress hormones and regulates: - Blood pressure  - Blood volume - Fluid balance - Inflammation Pancreas - Dual function: endocrine and exocrine - Alpha cells produce glucagon - Beta cells produce insulin - Regulates blood glucose levels - Maintains glucose between 70-110 mg/dL Reproductive System - Regulated by FSH and LH - Males: Testosterone production and sperm maturation - Females: Estrogen and progesterone production - Controls reproductive development and function Development and Aging - Endocrine system develops from three embryonic layers: - Endoderm - Ectoderm - Mesoderm Aging affects hormone production, particularly: - Growth hormone - Cortisol - Aldosterone - Sex hormones - Thyroid hormones Week 11 Lymphatic system The lymphatic system is a network of vessels that collects and returns lymph fluid to the bloodstream while transporting dietary fats and immune cells throughout the body. Primary Functions - Fluid Regulation: Drains excess interstitial fluid between tissues - Lymph Formation: Manages approximately 3 liters of the 20 liters of plasma that leak into tissue spaces daily - Disease Prevention: Damage to the system can lead to lymphedema, a serious condition involving protein-rich fluid accumulation Anatomical Components Primary Lymphoid Organs - Bone Marrow: Site of immune cell production and B-cell maturation; location of hematopoiesis - Thymus: Site of T-cell maturation Secondary Lymphoid Organs - Lymph Nodes: Bean-shaped filtering organs located throughout the body (500-600 total) - Spleen: Blood filtration and immune response coordination - Tonsils: Located in throat, important for developing immunity to oral pathogens - Lymphatic Vessels: Transport network for lymph fluid Lymph Nodes - Function as filters removing debris and pathogens - Located in groin, armpits, neck, chest, and abdomen - Contains: - Subcapsular sinus: Entry point with dendritic cells and macrophages - Cortex: Contains lymphoid follicles - Medulla: Contains B cells and plasma cells Lymphatic Vessels - Structure begins as open-ended capillaries - Contains one-way valves (semi-lunar valves) - Movement driven by body movements rather than heart pumping - Drainage pathways: - Right side drains into right subclavian vein - Remaining body areas drain into thoracic duct Immune System Components Barrier Defenses (First Line) - Skin: Primary physical barrier - Mucus membranes - Saliva containing lysozyme - Stomach acids - Respiratory tract cilia Immune Responses 1. Innate Immune Response (Second Line) - Quick but non-specific - Involves neutrophils, monocytes, macrophages, dendritic cells, NK cells - Provides initial defense against pathogens 2. Adaptive Immune Response (Third Line) - Slower but highly specific - Involves B-lymphocytes and T-lymphocytes - Develops immunological memory Antibodies and Immune Cells - Five antibody classes: IgM, IgD, IgG, IgA, IgE - B Cells: Produce antibodies - T Cells: Various immune functions - Natural Killer Cells: Destroy infected cells - Phagocytes: Engulf and destroy pathogens Inflammation and Immunity - Characterized by heat, redness, pain, and swelling - Triggered by tissue damage or infection - Involves: - Vasodilation - Increased vascular permeability - Recruitment of immune cells  - Formation of pus in severe infections Types of Immunity 1. Active Immunity - Natural: Developed through pathogen exposure - Artificial: Achieved through vaccination 2. Passive Immunity - Natural: Transfer from immune individual - Artificial: Direct antibody transfer - Provides immediate but temporary protection Week 12 urinary system Kidney Overview and Functions - Filters and cleanses blood - Eliminates waste material from bloodstream - Synthesizes hormones (renin, erythropoietin) - Regulates fluid and electrolyte balance - Stimulates bone marrow for blood cell production - Produces urine - Regulates pH balance - Helps regulate blood pressure Anatomical Structure External Anatomy - Paired kidneys located on either side of spine in retroperitoneal space - Left kidney: T12 to L3 vertebrae - Right kidney: Slightly lower due to liver - Protected by muscle, fat, and ribs (11th and 12th) - Size: 11-14 cm length, 6 cm wide, 4 cm thick - Weight: 125-175g (males), 115-155g (females) Internal Anatomy - Renal cortex (outer region) - Renal medulla (inner region) - 5-8 renal pyramids separated by renal columns - Renal papilla drains into minor calyx - Minor calyces connect to form major calyx - Major calyces connect to renal pelvis - Renal pelvis connects to ureter Blood Flow - Receives 25% of cardiac output at rest - Blood flow pathway: - Renal arteries - Segmental arteries - Interlobar arteries - Arcuate arteries  - Cortical radiate arteries - Afferent arterioles - Glomerulus Nephron Structure and Function Components - Glomerulus - Bowman's capsule - Proximal convoluted tubule - Loop of Henle - Distal convoluted tubule - Collecting ducts Types - Cortical nephrons (short loops of Henle) - Juxtamedullary nephrons (long loops of Henle) Urine Formation Process Three Main Steps 1. Glomerular Filtration - Passive process driven by hydrostatic pressure - Influenced by sympathetic nervous system 2. Tubular Reabsorption - Occurs in PCT, loop of Henle, DCT, collecting ducts - Recovers important substances like water, sodium, glucose - Uses active transport, simple diffusion, facilitated diffusion 3. Tubular Secretion - Removes unfiltered substances - Manages excess substances in blood - Handles toxins and antibiotics Hormonal Control - Antidiuretic Hormone (ADH) - Aldosterone - Atrial Natriuretic Hormone (ANH) - Renin-Angiotensin system - Parathyroid Hormone (PTH) Lower Urinary Tract Ureters - Retroperitoneal location - Uses peristaltic contractions for urine movement - Contains longitudinal and circular smooth muscle Bladder - Can hold 500-600 mL urine - Controlled by voluntary and involuntary actions - Micturition process requires intact sacral center and spinal cord Urethra - Different structure in males and females - Female urethra shorter (higher risk of infections) - Contains internal (involuntary) and external (voluntary) sphincters Homeostatic Functions - Vitamin D synthesis - Erythropoiesis through EPO production - Osmolarity regulation - pH balance maintenance - Blood pressure regulation through fluid volume control - Cooperation with lungs, liver, and adrenal cortex via renin-angiotensin-aldosterone system Week 13 sexual system ## Female Reproductive System ### Vulva - Consists of mons pubis, labia minora, labia majora, and vestibule - Mons pubis: fat pad over pubic bone, covered in pubic hair after puberty - Labia majora: hair-covered skin folds extending from mons pubis to perineal raphe - Labia minora: thinner, more pigmented folds medial to labia majora - Vestibule: region between labia minora ### Female Internal Organs - Ovaries: almond-sized gonads (2-3 cm), located near fimbriae - Uterus: muscular organ (5 cm × 7 cm) with three regions: - Fundus: superior portion above uterine tubes - Body: middle section - Cervix: narrow inferior portion projecting into vagina - Vagina: muscular canal (10 cm) containing protective microorganisms ### Breast Anatomy - Contains mammary glands (modified sweat glands) - Features nipple surrounded by pigmented areola - 15-20 lactiferous ducts connect to lactiferous sinuses - Milk-secreting cells organized in alveoli clusters ## Male Reproductive System ### Penis and Testes - Testes: spherical gonads (4-5 cm) producing sperm and androgens - Located in scrotum behind penis - Scrotum: muscular sack regulating temperature for sperm production - Sperm travels through ductus deferens during ejaculation ### Scrotum Function - Maintains optimal temperature for sperm production - Adapts to environmental temperature changes - Relaxes to increase surface area for heat loss ## Reproductive Cycles and Hormones ### Puberty - Marks sexual maturation - Controlled by hormones: - GnRH from hypothalamus - LH and FSH from anterior pituitary - Testosterone or estrogen from gonads ### Menstrual Cycle Three phases: 1. Menses Phase: Shedding of uterine lining 2. Proliferative Phase: Rebuilding of endometrium 3. Secretory Phase: Preparation for possible implantation ### Spermatogenesis - Continuous sperm production (100-300 million daily) - Involves mitosis and meiosis - Sperm structure includes: - Head containing DNA - Mid-piece with mitochondria - Tail for motility ## Reproductive Health ### Cervical Cancer Risk factors include: - Unprotected sex - Multiple sexual partners - Early sexual activity - HPV infection - Compromised immune system - Smoking ### Birth Control - Pills contain 21 active hormone pills and 7 placebos - Prevents ovulation through hormone regulation - Requires consistent timing for effectiveness ### Erectile Dysfunction Causes include: - Aging - Diabetes - Vascular disease - Psychiatric disorders - Prostate issues - Certain medications ## Hormonal Regulation ### Testosterone Regulation - Controlled by hypothalamus and pituitary gland - GnRH triggers LH and FSH production - Negative feedback loop involving testosterone and inhibin ### Sexual Response - Arousal triggered by mental and physical stimuli - Involves spinal cord nerve pathways - Orgasm initiated by sympathetic impulses - Requires proper vasodilation pathway function