Human Body Introduction PDF

LESSON 1: Introduction to the Human Body 1st Semester | A.Y. 2024-2025 GROSS ANATOMY OBJECTIVES ▪ From the latin word grossus meaning...

LESSON 1: Introduction to the Human Body 1st Semester | A.Y. 2024-2025 GROSS ANATOMY OBJECTIVES ▪ From the latin word grossus meaning “thick” or “massive” Define anatomy Define physiology ▪ Also known as Macroscopic Anatomy. Difference between gross and microscopic anatomy ▪ Can be conducted without a Identify the major levels of organization of the body from the simplest to the most complex microscope. ▪ Study of large body structures visible to the naked eye, such as the heart, lungs, WHAT IS ANATOMY AND PHYSIOLOGY? and kidneys. ANATOMY ▪ DISSECTION- an important part of gross ▪ derived from the Greek words ana (up) anatomy in which connective tissue is and tomia (cutting), meaning "to cut removed from between the body apart." organs so that the organs can be seen ▪ Study of internal and external body more clearly. structures also studies the structure of body parts and their relationships to one another. DIFFERENT FORMS OF GROSS ANATOMY ▪ Anatomy has a certain appeal because SURFACE ANATOMY it is concrete. ▪ study of general form of the body’s ▪ Body structures can be seen, felt, and surface examined closely. ▪ the study of internal structures as they relate to the overlying skin surface PHYSIOLOGY ▪ clinicians use it to locate appropriate ▪ Physio-physical blood vessels in which to feel pulses to ▪ Study of how living organisms perform draw blood their vital functions ▪ It also concerns the function of the body, REGIONAL ANATOMY in other words, how the body parts work ▪ anatomical organization of specific and carry out their life-sustaining areas of the body such as head, neck or activities. trunk HUMAN ANATOMY ▪ Study of the structure of the human SECTIONAL ANATOMY body ▪ study of the relationship of body’s structures by examining cross sections TWO PARTS OF HUMAN ANATOMY of the tissue or organ CLINICAL ANATOMY LECTURE 1 | MC 1 LEC Ars ▪ includes a number of subspecialties important in clinical practice LEVELS OF STRUCTURAL ORGANIZATION ▪ Examples: Pathological, Radiographic, CHEMICAL LEVEL Surgical Anatomy ATOM → MOLECULE ▪ Atom SYSTEMIC ANATOMY o building blocks of matter ▪ study of the structure of organ system, o they also participate in chemical which are groups of organs that reactions function together in a coordinated o CHONPCaS: Carbon (C), Hydrogen manner. (H), Oxygen (O), Nitrogen (N), ▪ Examples: Skeletal System, Muscular Phosphorus (P), Calcium (Ca), and System, Cardiovascular System Sulfur (S), are essential for maintaining life. DEVELOPMENTAL ANATOMY ▪ Molecules ▪ describes the changes in form that take o formed by two or more atoms place between conception and o DNA and glucose (essential adulthood molecules) o “Blood sugar”: another term for MICROSCOPIC ANATOMY glucose ▪ also known as histology ▪ deals with structures too small to be CELLULAR LEVEL seen with the naked eye MOLECULE → CELL ▪ Under this type of anatomy, we use Cell microscopes o basic unit of life ▪ SUBDIVISIONS o smallest living units in the human o Cytology- internal structure of the body. individual cells, the simplest units of o EXAMPLES: muscle cells, nerve cells, life. etc. o Histology- examination of the tissues TISSUE LEVEL ▪ Types of Microscopes: CELLS → TISSUES o DISSECTING MICROSCOPE ▪ Tissues ▪ tissue structure o are groups of similar cells that o LIGHT MICROSCOPE have a common function ▪ basic details of the cell ▪ FOUR BASIC TYPES OF TISSUES THAT structure MAKE UP ALL THE ORGANS o ELECTRON MICROSCOPE o EPITHELIAL ▪ individual molecules only ▪ covers the body surface nanometers across and lines its cavities LECTURE 1 | MC 1 LEC Ars o CONNECTIVE o Every living organism should ▪ supports the body and maintain its boundaries so that its protects its organs internal environment remains o MUSCULAR distinct from its external ▪ provides movement environment. o NERVOUS o EXAMPLE: Our cells are lined with a ▪ provides fast internal semi-permeable membrane that communication by serves as a covering; our body is transmitting electrical covered by INTEGUMENTARY SYSTEM impulses (skin) to protect the organs from ORGAN LEVEL pathogens TISSUES → ORGANS ▪ MOVEMENT Organ o activities promoted by the ▪ Discrete structure composed of at least muscular system, such as two tissue types that perform a specific propelling ourselves from one place function for the body to another by running or swimming and manipulating the external ORGAN SYSTEM LEVEL environment with our nimble fingers ORGANS → ORGAN SYSTEM ▪ RESPONSIVENESS/ EXCITABILITY Organ System o ability to sense changes (which ▪ Consists of related organs with a serve as stimuli) in the environment common function and then respond to them ▪ EXAMPLE: DIGESTIVE SYSTEM- breaks ▪ DIGESTION down and absorbs nutrients from the o The breaking down of ingested food (mouth, salivary glands, foodstuff into simple molecules that esophagus, pharynx (throat), stomach, can be absorbed into the blood small intestine, large intestine, liver, ▪ METABOLISM gallbladder, and pancreas. o Includes all chemical reactions that occur within body cells ORGANISM LEVEL o Catabolism [Complex to Simple] ORGAN SYSTEM → ORGANISM breaking down into simpler Organism building blocks ▪ represents the sum of all structural o Anabolism [Simple to Complex] levels working together to keep us alive. synthesizing more complex cellular structures from simpler substances NECESSARY LIFE FUNCTIONS o Cellular respiration using nutrients and oxygen ▪ MAINTAINING LIFE BOUNDARIES to produce ATP (adenosine LECTURE 1 | MC 1 LEC Ars triphosphate) – energy-rich 2) OXYGEN molecules that power a. 20% of the air we breathe is Oxygen cellular activities (O2). Chemical reactions that release ▪ EXCRETION energy from foods are oxidative o Process of removing waste/ excreta reactions that require oxygen. o EXAMPLES: 3) WATER Digestive- undigested food a. accounts for 60-80% of the body (feces) weight Urinary- nitrogen- b. provides a watery environment for containing wastes such as chemical reactions urea (urine) Respiratory- (carbon 4) NORMAL BODY TEMPERATURE dioxide) a. 98.6 Fahrenheit (37 Celsius) ▪ REPRODUCTION o process by which organisms 5) ATMOSPHERIC PRESS replicate themselves. a. the force that air exerts on the ▪ GROWTH surface of the body. o the irreversible increase of an b. In high altitudes, where atmospheric organism's size over a given period pressure is lower, and the air is thin, gas exchange may be inadequate to SURVIVAL NEEDS support cellular metabolism. ▪ The main goal of all body systems is to HOMEOSTASIS maintain life. ▪ comes from Greek word homeo “similar’ ▪ involves nutrients (food), oxygen, water, + stasis “state of standing” and appropriate temperature and ▪ describe its ability to maintain relatively atmospheric pressure. stable internal conditions even though the outside world changes continuously 1) NUTRIENTS ▪ Failure to maintain homeostasis soon a. Carbohydrates leads to illness or death. i. primary energy fuel for body cells. b. Calcium MECHANISMS OF HOMEOSTATIC REGULATION i. necessary for blood clotting. c. Minerals & vitamins HOMEOSTATIC REGULATION i. required for the chemical reactions adjustment of physiological systems in cells and oxygen transport in the to preserve homeostasis. blood. INVOLVES TWO GENERAL MECHANISMS ▪ AUTOREGULATION LECTURE 1 | MC 1 LEC Ars process occurs when a cell, tissue, ▪ information (output) then flows from the organ, or organ system adjusts in control center to the third component, response to environmental change. the effector change in temperature, our skin ▪ Efferent pathway (↓)-information flows “chicken skin” because it contracts from the control center to the effector due to change in temp ▪ EXTRINSIC REGULATION EFFECTOR process that results from the ▪ A cell or organ that responds to the activities of the nervous system or commands of the control center and endocrine system whose activity either opposes or organ systems detect an enhances the stimulus. environmental change and send an ▪ The results of the response then FEED electrical signal (nervous system) or BACK to influence the effect of the chemical messenger (endocrine stimulus, either reducing it (in negative system) to control or adjust the feedback) so that the whole control activities of another or many other process is shut off or enhancing it (in systems simultaneously. positive feedback) so that the whole process continues at an even faster rate. PROCESS OF HOMEOSTATIC REGULATION NEGATIVE FEEDBACK MECHANISM ▪ A way of counteracting change. ▪ The output shuts off the original effect of the stimulus or reduces its intensity ▪ MAIN GOAL: Preventing sudden severe changes within the body. ▪ EXAMPLES: ENDOCRINE SYSTEM- insulin controls blood sugar (glucose). As blood RECEPTOR sugar rises, receptors sense this change, ▪ A sensor that is sensitive to a particular and the pancreas (the control center) stimulus or environmental change secretes insulin into the blood. Change, in ▪ Stimuli- responds to changes, by turn, prompts body cells to absorb more sending information (input) to the glucose, removing it from the second component bloodstream, causing blood sugar to fall ▪ Afferent pathway (↓)- Input flows from and the stimulus for insulin release to the receptor to the control center end. CONTROL CENTER POSITIVE FEEDBACK MECHANISM ▪ Analyze the input it receives and determine the appropriate response or course of action. LECTURE 1 | MC 1 LEC Ars ▪ The result or response enhances the original stimulus to accelerate the response. ▪ Two familiar examples of their use as homeostatic mechanisms are the enhancement of labor contractions a. It protects and supports body organs during birth and blood clotting. and provides a framework for the o LABOR- during labor, the muscles to use to cause movement. hypothalamus secretes oxytocin, Blood cells are formed within bones. causing the contractions to become Bones store minerals. more frequent and powerful. b. 206 Bones, Joints o BLOOD CLOTTING- When blood loss C. MUSCULAR SYSTEM occurs due to a wound, the body activates a positive feedback loop to clot the blood and halt the bleeding. The injured blood vessel releases substances that start clotting, with platelets sticking to the site and a. Allows manipulation of the releasing chemicals to gather more environment, locomotion, and facial platelets. This process rapidly expression. Maintains posture and accelerates, attracting more produces heat. platelets to enlarge the clot until the b. Skeletal Muscles bleeding stops. D. NERVOUS SYSTEM 11 SYSTEMS OF THE HUMAN BODY A. INTEGUMENTARY SYSTEM a. As the fast-acting control system of the body, it responds to internal and a. Forms the external body covering and external changes by activating protects deeper tissues from injury appropriate muscles and glands. protects deeper tissues from injury. b. Brain, Neurons, Spinal Cord Synthesizes vitamin D and houses E. ENDOCRINE SYSTEM cutaneous receptors (pain, pressure, etc.) and sweat and oil glands. b. Hair, Skin, Nails B. SKELETAL SYSTEM LECTURE 1 | MC 1 LEC Ars b. Red bone marrow, thymus, lymphatic vessels, spleen, lymph nodes, thoracic duct H. RESPIRATORY SYSTEM a. Glands secrete hormones that regulate growth, reproduction, and nutrient use (metabolism) by body cells. b. Thyroid Gland, thymus, Adrenal Gland, a. Keeps blood constantly supplied with. Pancreas, Pineal Gland, pituitary gland, oxygen and removes carbon dioxide. ovary, testes The gaseous exchanges occur through. the walls of the air sacs of the F. CARDIOVASCULAR SYSTEM lungs. b. Nasal cavity, pharynx, larynx, trachea, lungs, bronchus I. DIGESTIVE SYSTEM a. Blood vessels transport blood, which carries oxygen, carbon dioxide, nutrients, wastes, etc. The heart pumps blood. b. Heart and blood vessels a. Breaks down food into absorbable units that enter the blood for G. LYMPHATIC SYSTEM/ IMMUNITY distribution to body cells. Indigestible foodstuffs are eliminated as feces. b. Oral Cavity, esophagus, liver, stomach, small intestine, large intestine, rectum, anus a. Picks up fluid leaked from blood J. URINARY SYSTEM vessels and returns it to blood. Disposes of debris in the lymphatic stream. White blood cells (lymphocytes) are involved in immunity. The immune response mounts the attack against foreign substances within the body. LECTURE 1 | MC 1 LEC Ars a. Eliminates nitrogenous wastes from the body. Regulates water, electrolyte, and acid-base balance of the blood. b. Kidney, ureter, urethra, urinary bladder K. MALE REPRODUCTIVE SYSTEM ABDOMINOPELVIC REGIONS a. Overall function is the production of offspring. Testes produce sperm and male sex hormones, and male ducts and glands aid in the delivery of sperm to the female reproductive tract. b. Prostate gland, penis, testes, scrotum ducus (vas deferens) ▪ UMBILICAL REGION- the centermost c. region deep to and surrounding the L. FEMALE REPRODUCTIVE SYSTEM umbilicus ▪ EPIGASTRIC REGION- located superior to the umbilical region (epi =upon, above; gastri = belly). ▪ THE HYPOGASTRIC (PUBIC) REGION- located inferior to the umbilical region a. Ovaries produce eggs and female sex (hypo = below). hormones. The remaining female ▪ The right and left iliac, or inguinal, structures serve as sites for fertilization regions are located lateral to the and development of the fetus. The hypogastric region (iliac = superior part mammary glands of female breasts of the hip bone). produce milk to nourish the newborn. ▪ The right and left lumbar regions lie b. Mammary glands, ovary, uterus, lateral to the umbilical region (lumbus = vagina, fallopian tube loin). ▪ The right and left hypochondriac ANATOMICAL REGIONS regions lie lateral to the epigastric region and deep to the ribs (chondro = ABDOMINOPELVIC QUADRANTS cartilage). -Intersect at the umbilicus LECTURE 1 | MC 1 LEC Ars ANATOMICAL POSITION AND DIRECTIONAL DIRECTIONAL TERMS TERMS TWO FUNDAMENTAL DIVISIONS OF OUR BODY: AXIAL - which makes up the main axis of our body, includes the head, neck, and trunk [80 bones] APPENDICULAR- consists of the appendages, or limbs, which are attached to the body's axis [126 bones] ANATOMICAL LANDMARKS BODY PLANES AND SECTION SAGITTAL PLANE ▪ is a vertical plane that divides the body into right and left parts. MEDIAN/MIDSAGITTAL- divides the body into two equal parts vertically. PARASAGITTAL- Other sagittal planes offset (unequal) from the midline. LECTURE 1 | MC 1 LEC Ars FRONTAL/CORONAL PLANE ▪ divide the body into anterior and BODY CAVITIES AND MEMBRANES posterior parts TRANSVERSE/ CROSS SECTION PLANE BODY CAVITIES ▪ runs horizontally from right to left, ▪ DORSAL BODY CAVITY/LATERAL VIEW dividing the body into superior and Cranial Cavity: fills most of the inferior parts upper part of the skull and contains the brain Vertebral/Spinal Cavity: a very long, narrow cavity inside the vertebral column. It runs the length of the trunk and contains the spinal cord. ▪ VENTRAL CAVITY OBLIQUE SECTION Thoracic Cavity: the chest is ▪ are cuts made diagonally between the divided into two pleural cavities and horizontal and the vertical planes. the pericardial cavity. 2 Pleural cavities: hold the lungs Pericardial cavity: holds the heart LECTURE 1 | MC 1 LEC Ars Abdominopelvic Cavity: fills the lower half of the trunk and is subdivided into the abdominal and pelvic cavities. Abdominal cavity: holds digestive organs, the kidneys Pelvic cavity: holds reproductive organs and organs of excretion MEMBRANES IN THE VENTRAL BODY CAVITY ▪ SEROSA/ SEROUS MEMBRANE covers the walls of the ventral body cavity and the organs it contains To prevent friction and membrane to membrane touch. PARIETAL SEROSA part of the membrane lining the cavity walls External VISCERAL SEROSA covering the organs in the cavity Internal ▪ SEROUS FLUID- a lubricating fluid which separates the serous membranes