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Semester 1: Human Anatomy and Physiology
Overview of anatomy: medical terminology, anatomical variations, body organization, systemic anatomy
Overview of anatomy: medical terminology, anatomical variations, body organization, systemic anatomy
Medical Terminology
Medical terminology is a language used to describe the components of the human body, its functions, and related medical conditions. It often includes prefixes, suffixes, and root words derived from Latin and Greek. Understanding this terminology is essential for clear communication in medical fields. Terms are categorized into anatomical terms, diagnostic terms, procedures, and specialties.
Anatomical Variations
Anatomical variations refer to differences in the structure of organs or systems among individuals. These variations can be minor, such as differences in the branching of blood vessels, or major, such as congenital anomalies. Recognizing these variations is crucial in clinical practice as they may affect diagnosis, treatment, and surgical procedures.
Body Organization
The human body is organized into several levels of complexity: cells, tissues, organs, systems, and the organism as a whole. Cells are the basic unit of life, combining to form tissues. Tissues group together to create organs, which in turn collaborate within organ systems to maintain homeostasis.
Systemic Anatomy
Systemic anatomy focuses on the structure and function of individual organ systems within the body. Major systems include the skeletal, muscular, circulatory, respiratory, digestive, nervous, endocrine, urinary, and reproductive systems. Each system comprises specific organs that work together to perform certain functions essential for life.
Bones and joints: types, classification, innervation
Bones and Joints: Types, Classification, Innervation
Types of Bones
Bones are classified based on their shapes: 1. Long bones (e.g., femur, humerus) - cylindrical and longer than they are wide. 2. Short bones (e.g., carpals, tarsals) - cube-shaped. 3. Flat bones (e.g., skull, ribs) - thin and flattened. 4. Irregular bones (e.g., vertebrae, pelvis) - complex shapes.
Classification of Joints
Joints are classified based on structure and function: 1. Fibrous joints - dense connective tissue, no movement (e.g., suture of the skull). 2. Cartilaginous joints - cartilage, slight movement (e.g., intervertebral discs). 3. Synovial joints - fluid-filled cavity, free movement (e.g., knee, elbow).
Innervation of Bones and Joints
Bone tissue is innervated primarily by sensory nerves that detect pain and pressure. Joint innervation is provided by articular nerves, which also carry proprioceptive information, enabling the brain to sense joint position and movement.
Muscle tissue and muscular system: types of muscles, anatomy of liver, kidney, stomach
Muscle tissue and muscular system
Types of Muscles
Muscle tissue is categorized into three main types: skeletal, cardiac, and smooth muscles. Skeletal muscles are voluntary and striated, primarily responsible for movement. Cardiac muscle is involuntary and striated, found in the heart, and responsible for pumping blood. Smooth muscle is involuntary and non-striated, located in the walls of internal organs. Each type has unique structural and functional characteristics.
Anatomy of the Liver
The liver is a large, reddish-brown organ located in the upper right abdomen. It has two main lobes, separated by the falciform ligament. The liver performs crucial functions including detoxification, protein synthesis, and the production of biochemicals necessary for digestion. It contains hepatocytes, bile ducts, and a rich blood supply from the hepatic artery and portal vein.
Anatomy of the Kidney
The kidneys are bean-shaped organs located on either side of the spine, just below the rib cage. Each kidney has an outer cortex and an inner medulla, with the renal pelvis collecting urine. Kidneys play a vital role in filtering blood, regulating electrolytes, and maintaining acid-base balance. Nephrons are the functional units of kidneys, responsible for urine formation.
Anatomy of the Stomach
The stomach is a J-shaped organ located between the esophagus and the small intestine. It has four main regions: the cardia, fundus, body, and pylorus. The stomach plays a critical role in digestion, mixing food with gastric juices, and breaking it down into chyme. The stomach wall consists of mucosa, submucosa, muscularis, and serosa layers, which facilitate its functions.
Cardiovascular system: blood components, coagulation, blood groups, lymph, heart structure and function, cardiac output, pulse, heart sounds, cardiac rhythm disorders
Blood Components
Blood consists of various components including red blood cells, white blood cells, platelets, and plasma. Red blood cells transport oxygen to tissues and remove carbon dioxide. White blood cells are vital for immune response. Platelets play a crucial role in blood clotting, while plasma carries nutrients, hormones, and proteins.
Coagulation
Coagulation is the process by which blood changes from a liquid to a gel, forming a blood clot. This involves a series of complex biochemical reactions including the activation of clotting factors, which leads to the conversion of fibrinogen to fibrin. Proper coagulation is essential to prevent excessive bleeding.
Blood Groups
Blood groups are classified based on the presence or absence of antigens on the surface of red blood cells. The major blood group systems include ABO and Rh factor. ABO groups are classified as A, B, AB, and O, while Rh factor determines positive or negative blood types. Understanding blood groups is crucial for safe blood transfusions.
Lymph
Lymph is a clear fluid that circulates through the lymphatic system, transporting cells and substances, including immune cells, throughout the body. It plays an essential role in maintaining fluid balance and supporting the immune system by filtering out foreign substances.
Heart Structure and Function
The heart is a muscular organ divided into four chambers: the right atrium, right ventricle, left atrium, and left ventricle. The right side of the heart receives deoxygenated blood and pumps it to the lungs, while the left side pumps oxygenated blood to the rest of the body. Key structures include valves that ensure unidirectional blood flow.
Cardiac Output
Cardiac output is the volume of blood pumped by the heart per minute, calculated as stroke volume multiplied by heart rate. It is a critical measure of heart function and influences tissue perfusion. Factors that affect cardiac output include physical activity, body position, and overall cardiovascular health.
Pulse
Pulse refers to the rhythmic expansion and contraction of arteries as blood is pumped by the heart. It can be felt at various pulse points across the body. The pulse rate is an important indicator of heart health, with typical resting rates ranging from 60 to 100 beats per minute.
Heart Sounds
Heart sounds are generated by the closure of heart valves during the cardiac cycle. The two primary sounds, 'lub' (S1) and 'dub' (S2), correspond to the closure of the atrioventricular and semilunar valves, respectively. Additional sounds may indicate abnormalities, such as murmurs.
Cardiac Rhythm Disorders
Cardiac rhythm disorders, or arrhythmias, involve irregular heartbeats that can affect blood circulation. Common types include atrial fibrillation, ventricular tachycardia, and bradycardia. Diagnosis and management require monitoring heart rhythm through ECG and may involve medication or procedures to restore normal rhythm.
Respiratory system: gas diffusion, oxygen and CO2 transport, respiratory physiology
Gas Diffusion
Gas diffusion refers to the process by which oxygen and carbon dioxide move across the alveolar membrane in the lungs. This occurs primarily due to concentration gradients, with oxygen diffusing from the alveoli into the blood and carbon dioxide diffusing from the blood into the alveoli. Factors that influence gas diffusion include membrane thickness, surface area, and the partial pressures of the gases.
Oxygen Transport
Oxygen transport involves the movement of oxygen from the lungs to the tissues. Hemoglobin in red blood cells is the primary transport molecule, binding to oxygen in a reversible manner. Each hemoglobin molecule can carry up to four oxygen molecules. Various factors, such as pH, temperature, and levels of carbon dioxide, can affect hemoglobin's affinity for oxygen, a phenomenon known as the Bohr effect.
Carbon Dioxide Transport
Carbon dioxide is transported from the tissues back to the lungs in three main forms: dissolved in plasma, as bicarbonate ions (HCO3-), and bound to hemoglobin (carbaminohemoglobin). The conversion of CO2 to bicarbonate is facilitated by the enzyme carbonic anhydrase, which plays a crucial role in maintaining the acid-base balance in the body.
Respiratory Physiology
Respiratory physiology studies the mechanics of breathing and gas exchange. The process of breathing (ventilation) involves inhalation, where the diaphragm contracts, and exhalation, where it relaxes. The respiratory rate is regulated by the medulla oblongata, responding to the levels of carbon dioxide and oxygen in the blood. Additionally, the concepts of tidal volume, vital capacity, and total lung capacity summarize the various volumes of air exchanged during breathing.
Excretory system: urine formation, composition, micturition, renal acid-base regulation
Excretory system
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Urine formation is the process by which the kidneys filter blood to create urine, which is excreted from the body to remove waste products.
Filtration: Blood is filtered in the glomerulus, where water, ions, and small molecules pass into the nephron.
Reabsorption: Essential substances such as glucose and certain ions are reabsorbed back into the bloodstream from the renal tubule.
Secretion: Additional waste products are secreted into the tubule from the blood for excretion.
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Urine composition consists of various substances that reflect metabolic processes in the body.
Water: approximately 95% of total urine volume.
Urea: a breakdown product of protein metabolism.
Creatinine: a waste product from muscle activity.
Uric acid: derived from the metabolism of purines.
Electrolytes: such as sodium, potassium, chloride, and others.
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Micturition is the process of expelling urine from the bladder through the urethra.
Filling phase: The bladder fills with urine, stretching the bladder wall.
Storage phase: The internal and external sphincters remain contracted to temporarily hold urine.
Voiding phase: Signals from the nervous system trigger the sphincters to relax, allowing urine to flow out.
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The kidneys play a critical role in maintaining acid-base balance in the body by regulating hydrogen ion concentration and bicarbonate levels.
Bicarbonate reabsorption: The kidneys reabsorb bicarbonate from urine to neutralize excess acids.
Hydrogen ion secretion: The kidneys excrete hydrogen ions into the urine to maintain pH balance.
Digestive system: secretion, digestion, assimilation of biomolecules, gastrointestinal hormones
Digestive system: secretion, digestion, assimilation of biomolecules, gastrointestinal hormones
Secretion in the Digestive System
Secretion refers to the production and release of substances that aid in digestion. Key secretions include saliva, gastric juice, bile, and pancreatic juice. Saliva contains enzymes like amylase that begin carbohydrate digestion. Gastric juice, composed of hydrochloric acid and pepsinogen, initiates protein digestion. Bile facilitates fat digestion and absorption, while pancreatic juice contains enzymes that further digest carbohydrates, proteins, and fats.
Digestion Process
Digestion encompasses both mechanical and chemical processes. Mechanical digestion involves the physical breakdown of food (chewing and grinding). Chemical digestion utilizes enzymes to break down complex biomolecules into simpler forms. The digestion of carbohydrates begins in the mouth, proteins in the stomach, and fats in the small intestine. Each stage of digestion is dependent on the secretion of various enzymes and substances.
Assimilation of Biomolecules
Assimilation is the process by which the body absorbs and utilizes digested nutrients. After digestion, nutrients are absorbed primarily in the small intestine through villi and microvilli, which increase surface area. Carbohydrates are absorbed as monosaccharides, proteins as amino acids, and fats as fatty acids and glycerol. These nutrients are then transported to cells for energy, growth, and repair.
Gastrointestinal Hormones
Gastrointestinal hormones play a crucial role in regulating digestive processes. Key hormones include gastrin, secretin, and cholecystokinin (CCK). Gastrin stimulates gastric juice secretion and motility. Secretin regulates bicarbonate secretion from the pancreas and inhibits gastric secretion. CCK promotes bile release from the gallbladder and pancreatic enzyme secretion. These hormones coordinate the digestive process and ensure efficient nutrient absorption.
Nervous system: neuron structure, action potential, synapse, neuromuscular junction, neurotransmitters
Nervous system
Neuron Structure
Neurons are the fundamental units of the nervous system. They consist of three main parts: the cell body (soma), dendrites, and axon. The cell body contains the nucleus and organelles. Dendrites receive signals from other neurons, while the axon transmits impulses away from the cell body. Myelin sheath, formed by Schwann cells, insulates the axon and speeds up transmission.
Action Potential
Action potential is a rapid change in membrane potential that occurs when a neuron is activated. It involves depolarization followed by repolarization. Voltage-gated ion channels open, allowing Na+ influx and K+ efflux, creating a wave of electrical activity along the axon, propagating the signal.
Synapse
Synapses are the junctions where neurons communicate. They can be electrical or chemical. Chemical synapses involve neurotransmitter release from the presynaptic neuron binding to receptors on the postsynaptic neuron, influencing its action potentials. Synaptic transmission is essential for neuronal communication.
Neuromuscular Junction
Neuromuscular junctions are specialized synapses between motor neurons and skeletal muscle fibers. At this junction, the neurotransmitter acetylcholine is released, binding to receptors on the muscle membrane, leading to muscle contraction. It is crucial for voluntary movement.
Neurotransmitters
Neurotransmitters are chemical messengers that transmit signals across synapses. Various types exist, including excitatory (like glutamate) and inhibitory (like gamma-aminobutyric acid or GABA) neurotransmitters. The balance between these is key for normal brain function and signal processing.
Reproductive system: male and female reproductive anatomy and physiology, hormonal functions, menstrual cycle, pregnancy, lactation
Reproductive system
Male reproductive anatomy and physiology
The male reproductive system includes structures such as the testes, epididymis, vas deferens, seminal vesicles, prostate gland, and penis. The testes produce sperm and testosterone, while the epididymis stores and matures sperm. The vas deferens transports sperm during ejaculation. Seminal vesicles and prostate gland contribute to seminal fluid.
Female reproductive anatomy and physiology
The female reproductive system comprises the ovaries, fallopian tubes, uterus, cervix, and vagina. Ovaries produce eggs and hormones like estrogen and progesterone. Fallopian tubes transport the egg from the ovary to the uterus. The uterus supports fetal development during pregnancy, while the vagina serves as the birth canal.
Hormonal functions
The reproductive system is governed by hormones such as testosterone in males and estrogen and progesterone in females. In males, testosterone is responsible for the development of male secondary sexual characteristics and sperm production. In females, estrogen regulates the menstrual cycle and the development of female secondary sexual characteristics, while progesterone prepares the uterus for pregnancy.
Menstrual cycle
The menstrual cycle is a monthly process involving the thickening of the uterine lining and the release of an egg. It has four phases: menstrual, follicular, ovulation, and luteal. It typically lasts about 28 days and is regulated by hormonal changes.
Pregnancy
Pregnancy occurs when a sperm fertilizes an egg, leading to the development of an embryo. It spans approximately nine months, during which the embryo develops into a fetus. Hormones like hCG, progesterone, and estrogen play crucial roles in maintaining the pregnancy and supporting fetal development.
Lactation
Lactation is the process of milk production in the breasts following childbirth. It is initiated by hormonal changes, particularly the release of prolactin and oxytocin. Prolactin stimulates milk production, while oxytocin is responsible for milk ejection during breastfeeding.
