Chap 1 - Introduction to Physiology - FHSC 203 PDF

Introduction to Human Physiology FHSC 203 Chap 1 - The Human Body: An Orientation Introduction ü Anatomy: “Ana” means up or apart “Tomos” means to cut Introduction § Describes the structures of the body: 1. what they are made of 2. where they are located 3. associated...

Introduction to Human Physiology FHSC 203 Chap 1 - The Human Body: An Orientation Introduction ü Anatomy: “Ana” means up or apart “Tomos” means to cut Introduction § Describes the structures of the body: 1. what they are made of 2. where they are located 3. associated structures Introduction ü Physiology is the study of how living organisms perform the various functions of life. § It is where we figure out how stuff works 1. How do muscles contract? 2. How do we run? 3. How does our heart beat? KEY CONCEPT ü All physiological functions are performed by specific anatomical structures ü Principle of complementarities says that structure and function are complementary § Function always reflects structure § What a structure can do depends on its specific form Introduction ü Fields of Anatomy: 1. Gross Anatomy: visible to naked eye Ø Large structures Ø Easily observable Introduction 1. Gross Anatomy § Regional: all structures in one part of the body (such as the abdomen or leg) Introduction § Systemic: gross anatomy of the body studied by organ system Introduction § Surface: study of internal structures as they relate to the overlying skin Introduction 2. Microscopic Anatomy: § Cytology: study of the cell § Histology: study of tissues Introduction 3. Developmental Anatomy: traces structural changes that occur in the body throughout an organism's lifespan § Embryology Levels of structural organization Atom An association of cells with the same general structure and function Cell An association of several tissue types that carry out a specific function Tissue Smallest unit of an element of matter Organ Smallest living unit Organ A single individual of a particular life form system Levels of structural organization Levels of structural organization 1. Chemical level a. Atoms are the smallest unit of an element of matter b. Molecules i. Inorganic: H2O; Salts; H+; OH- ii. Organic: lipids, carbohydrates, proteins, nucleic acids Levels of structural organization 2. Cells are the basic living unit of the body. ü Cells differ from one another but all share some common characteristics Cells commonalities ü Oxygen required for energy release ü Similar chemical mechanisms for energy generation ü Deliver the end products of their chemical reactions into the surrounding fluids ü Have the ability to reproduce ü Cellular regeneration from injury ü Maintain Homeostasis Tissues 3. Tissues are groups of cells with a common structure (form) and function (job). ü There are four main tissues in the body: § Epithelium § Muscle § Connective tissue § Nervous tissue Tissues Tissues a. Epithelial tissue ü Often called epithelium, it is comprised of tightly packed cells, arranged to form layers. ü Epithelial cells are constantly renewing and replacing the dead or inactive cells. Tissues ü The two main epithelial tissue types are: § Glandular: found in exocrine and endocrine glands § Lining epithelium: forms the outer layer of the skin and in some internal organs ü They have distinct inner and outer surfaces: § Inner surfaces = basal ends of the epithelial cells § Outer surfaces = apical ends of the epithelial cells Tissues ü The number of cell layers & the shape of the cells in the top layer can classify epithelium. i. By shape a) squamous - flat and scale-like b) cuboidal - as tall as they are wide c) columnar - tall, column-shaped Tissues ii. By cell arrangement a) simple epithelium - single layer of cells (usually for absorption and filtration) b) stratified epithelium - stacked up call layers (protection from abrasion (rubbing) - mouth, skin.) Tissues Tissues b. Connective tissue ü Connective tissue is made up of cells and protein fibers and provides support for other body tissues. ü The main proteins in connective tissue are: § collagen § elastin Tissues ü There are five types of connective tissue: § Loose connective tissue- Including adipose tissue; fibers & many cell types in gelatinous matrix, found in skin, & surrounding blood vessels, nerves, and organs § Dense connective tissue- Bundles of parallel collagen fibers& fibroblasts, found in tendons& ligaments § Blood § Bone- Provides rigid, structural support § Cartilage- Occurs in the human body in the ears, tip of the nose, and at joints such as the knee and between bones of the spinal column Tissues Tissues c. Muscle tissue ü Muscle tissue provides stability to the skeleton and internal organs and allows body movement. ü Muscle tissue makes up approximately 60% of the body’s mass and there are three types of muscle tissue. Tissues ü These are: § Cardiac: found in the heart § Skeletal: usually attached to bone § Smooth: found in walls of blood vessels in digestive system, respiratory system and the eye Tissues d. Nervous tissue ü The nervous system is made up of the: § Central Nervous System (CNS) § Peripheral Nervous System (PNS) ü Comprised of neural and nervous tissue, the CNS and PNS transmit signals from the brain to the body parts (muscles, glands, sense organs) to activate a response. Tissues ü Consists of only two cell types in the central nervous system (CNS) & peripheral nervous system (PNS): § Neurons - Cells that convert stimuli into electrical impulses to the brain § Neuroglia – supportive cells Tissues Tissue Cell Extracellular   Function matrix Epithelial Aggregated Miniscule Line  surface  /  body   polyhedral cavities;;  Produce   cells glandular  secretions Connective Variable Abundant Provide  support  and   fixed  /  wandering protection cells Muscle Elongated Moderate Allow  for  movement contractile cells Nervous Intertwining None Transmit  electrical   elongated impulses processes Organs 4. Organs are the next level of organization in the body. ü An organ is a structure that contains at least two different types of tissue functioning together for a common purpose. ü There are many different organs in the body: the liver, kidneys, heart, even your skin is an organ. Organ system 5. Organ systems are composed of two or more different organs that work together to provide a common function. ü Controlled and regulated to achieve constancy in the internal environment of the organism. Organ system overview Integumentary system § Forms the external body covering § Protects deeper tissue from injury and drying out § Composed of the skin, sweat glands, oil glands, hair, and nails § Synthesizes vitamin D § Location of cutaneous nerve receptors Organ system overview Skeletal system § Composed of bone, cartilage, and ligaments § Protects and supports body organs § Provides the framework for muscles § Site of blood cell formation § Stores minerals Organ system overview Muscular system § Composed of muscles and tendons: Ø Skeletal Ø Smooth Ø Cardiac § Allows manipulation of the environment, locomotion, and facial expression § Maintains posture § Produces heat Organ system overview Nervous system § Composed of the brain, spinal column, and nerves § Is the fast-acting control system of the body (it relays electrical signals through the body § Responds to stimuli by activating muscles and glands Organ system overview Cardiovascular system § Composed of the heart and blood vessels § The heart pumps blood § The blood vessels transport blood throughout the body § The main role is to transport nutrients, gases (such as oxygen and CO2) hormones and wastes through the body Organ system overview Endocrine system § The main role of the endocrine system is to relay chemical messages through the body § In conjunction with the nervous system, these chemical messages help control physiological processes such as metabolism, growth, reproduction… Organ system overview Lymphatic system § Composed of red bone marrow, thymus, spleen, lymph nodes, and lymphatic vessels § Picks up fluid leaked from blood vessels and returns it to blood § Disposes of debris in the lymphatic stream § Houses cells Involved in immunity- destroys bacteria and tumor cells Organ system overview Respiratory system § Composed of the nasal cavity, pharynx, trachea, bronchi, and lungs § The main role of the respiratory system is to provide gas exchange between the blood and the environment § Primarily, oxygen is absorbed from the atmosphere into the body and carbon dioxide is expelled from the body Organ system overview Digestive system § Composed of the oral cavity, esophagus, stomach, small intestine, large intestine, rectum, anus, and liver § Breaks down food into absorbable units that enter the blood § Eliminates indigestible foodstuffs as feces Organ system overview Urinary system § Composed of kidneys, ureters, urinary bladder, and urethra § Regulates water, electrolyte, and pH balance of the blood § Eliminates nitrogenous wastes from the body Organ system overview Reproductive system § The main role of the reproductive system is to manufacture cells that allow reproduction: production of offspring § In the male, sperm are created to inseminate egg cells produced in the female Organ system interrelationship § The integumentary system protects the body from the external environment § Digestive and respiratory systems, in contact with the external environment, take in nutrients and oxygen § Nutrients and oxygen are distributed by the blood § Metabolic wastes are eliminated by the urinary and respiratory systems Necessary Life processes ü The basic processes of life include: § Organization: At all levels of the organizational scheme, there is a division of labour § Metabolism: all the chemical reactions that occur in the body § Responsiveness: ability to sense changes in the environment and respond to them § Movements: locomotion, propulsion (peristalsis), and contractility Necessary Life processes § Reproduction: cellular and organismal levels Ø Cellular – an original cell divides and produces two identical daughter cells Ø Organismal – sperm and egg unite to make a whole new person § Maintaining boundaries: the internal environment remains distinct from the external Ø Cellular level – accomplished by plasma membranes Ø Organismal level – accomplished by the skin § Growth: increase in size of a body part or of the organism § Differentiation: cells develop into tissues and organs Necessary Life processes § Respiration: exchange of oxygen and carbon dioxide between the cells and the external environment § Digestion: breakdown of ingested foodstuffs § Excretion: removal of wastes from the body Necessary Life processes ü All of the processes are interrelated. ü No part of the body, from the smallest cell to a complete body system, works in isolation. ü All function together, in fine-tuned balance, for the well being of the individual and to maintain life. Human survival needs ü Nutrients: chemical substances used for energy and cell building ü Oxygen: needed for metabolic reactions ü Water: provides the necessary environment for chemical reactions ü Maintaining normal body temperature: necessary for chemical reactions to occur at life-sustaining rates ü Atmospheric pressure: required for proper breathing and gas exchange in the lungs Homeostasis ü Ability to maintain a stable internal environment in an ever-changing outside world. ü All body systems working together to maintain a stable internal environment, respond to external and internal changes to function within a normal range (body temperature, fluid balance). ü The internal environment of the body is in a dynamic state of equilibrium. Homeostasis control mechanism ü Variables produce a change in the body ü The three interdependent components of control mechanisms: § Receptor – monitors the environments and responds to changes (stimuli). § Control center – determines the set point at which the variable is maintained. § Effectors – provides the means to respond to stimuli. Homeostasis control mechanism 3 Input: Control Information center   4 Output: sent  along   Information  sent afferent along  efferent pathway  to pathway  to Receptor  (sensor) Effector 2 Change   detected   by  receptor 5 Response  of effector  feeds 1 Stimulus:   Produces   back  to change influence in  variable magnitude  of stimulus  and Variable  (in  homeostasis) returns  variable to  homeostasis Homeostasis control mechanism ü Three main interdependent control pathways are: § Genetic (can also have both negative and positive feedback) § Negative feedback § Positive feedback Negative feedback ü It is the most common way negative to maintain homeostasis in the body. negative ü In negative feedback systems the response of the effector opposes the stimulus (shuts off the original stimulus). Negative feedback Positive feedback ü NOT a way to maintain homeostasis. ü The response of the effectors' output reinforces or exaggerates the stimulus (e.g. blood clotting). Positive feedback Body planes Body planes