Introduction to Anatomy & Physiology PDF

INTRODUCTION TO ANATOMY & PHYSIOLOGY Nur Hanisah Azmi, PhD Nutrition Program Faculty of Food Science and Nutrition, Universiti Malaysia Sabah OUTLINE By the end of this lecture, student should clearly understand: Definition of anatomy and physiology Overall organization of human body and fun...

INTRODUCTION TO ANATOMY & PHYSIOLOGY Nur Hanisah Azmi, PhD Nutrition Program Faculty of Food Science and Nutrition, Universiti Malaysia Sabah OUTLINE By the end of this lecture, student should clearly understand: Definition of anatomy and physiology Overall organization of human body and functional structures Concept of internal environment and homeostasis Principles of negative and positive feedback mechanisms Definition ANATOMY The science of body structures and relationships among them. PHYSIOLOGY The study of the functions of living matter. Selected branches of anatomy and physiology Living body functions are usually complementary to particular body structures.  Level of Organization and Body Systems Derrickson, Bryan H. Tortora, Gerard J. (2017)  Anatomical Position Anatomical position is descriptions of any region / part of the human body assume that it is in a standard position of reference. ▪ The subject stands erect facing the observer ▪ The head level and the eyes facing directly forward ▪ The lower limbs are parallel ▪ The feet are flat on the floor and directed forward ▪ The upper limbs are at the sides with the palms turned forward ▪ The vertebral column (spine) is straight and aligned, maintaining a natural and neutral curvature  Directional terms ► to describe the relative position and location of body parts, regions, and structures in relation to each other Body planes Imaginary flat surfaces that pass through the body parts. Sagittal plane - vertical plane that divides the body/ organ into right and left sides Midsagittal plane - passes through the midline of the body or an organ and divides it into equal right and left sides Para sagittal plane - divides the body or an organ into unequal right and left sides A frontal plane - divides the body or an organ into anterior (front) and posterior (back) portions Transverse plane - divides the body or an organ into superior (upper) and inferior (lower) portions Oblique plane - passes through the body or an organ at an oblique angle Midsaggital and Frontal Plane Section of the Brain Frontal Plane Section of the Kidney Planes divide the body in various ways to produce sections  Human body & homeostasis homeo- -stasis “sameness” “standing still” The maintenance of relatively stable conditions in the body’s internal environment. Dynamic – in response to changing conditions, the body’s parameters can shift among points in a narrow range that is compatible with maintaining life. Each structure, from the cellular level to system level perform functions that helps maintaining homeostasis. Disruptions to homeostasis often set in motion corrective cycles, called feedback systems, that help restore the conditions needed for health and life. ►60% of adult human body is fluid ►Intracellular fluid (ICF): fluid within cells. ►Extracellular fluid (ECF): fluid outside body cells. ► The ECF that fills the narrow spaces between cells of tissues is known as interstitial fluid ► ECF within blood vessels: blood plasma ► Within lymphatic vessels: lymph ► In and around the brain and spinal cord: cerebrospinal fluid (CSF) ► In joints: synovial fluid ► ECF of the eyes: aqueous humor and vitreous body  Extracellular Fluid: The “internal environment” @ “milieu interieur” ECF: The “internal environment” @ milieu interieur Exchanges between the external and internal environments Feedback System Components of the feedback system @ feedback control loop: ▪ Controlled condition ▪ Stimulus ▪ Receptor- sensor mechanism ▪ Control- integrator ▪ Effector Controlled condition (controlled variable) ► Each monitored variable, such as body temperature, blood pressure, or blood glucose level Stimulus ► Any disruption that changes a controlled condition Receptor ► A body structure that monitors changes in a controlled condition and sends input to a control center Control center in the body, e.g., the brain, ► Sets the narrow range or set point within which a controlled condition should be maintained ► Evaluates the input it receives from receptors, and generates output commands when they are needed ► Output from the control center typically occurs as nerve impulses, or hormones or other chemical signals Effector ► A body structure that receives output from the control center and produces a response or effect that changes the controlled condition ► Nearly every organ or tissue in the body can behave as an effector Operation of a feedback system +/- Example: ► A stimulus (↓ temperature) activates a receptor/ sensor (sensory nerve fibers) that sends input to a control center (hypothalamus), which then send an output to an effector (contracting muscle). ► The resulting heat that is produced maintains the temperature in a “normal range”. Types of feedback mechanism: 1 NEGATIVE FEEDBACK 2 POSITIVE FEEDBACK 1 NEGATIVE FEEDBACK ► Reverses a change in a controlled condition ► Inhibitory ► Produces an action that is the opposite/ reverse to the change that activated the system ► Responsible for maintaining homeostasis ► Much more common than positive feedback control system Homeostatic regulation of BP by NEGATIVE FEEDBACK Homeostasis regulation of blood pressure by NEGATIVE FEEDBACK Blood pressure (BP) is the force exerted by blood as it presses against the walls of blood vessels. When the heart beats faster or harder, BP increases and vice versa ► Some internal or external stimulus causes BP (controlled condition) to rise ► Baroreceptors (pressure-sensitive nerve cells located in the blood vessel walls) detect the higher pressure ► Baroreceptors send nerve impulses (input) to the brain (control center) ► Brain interprets the impulses and responds by sending nerve impulses (output) to the heart and blood vessels (effector) ► Heart rate decreases and blood vessels dilate, which cause BP to decrease (response) Other example.. 2 POSITIVE FEEDBACK ► Strengthen or reinforce a change in a controlled condition ► Stimulatory ► Tend to produce destabilizing effects and disrupt homeostasis ► The action of positive feedback system continues until it is interrupted by some mechanism outside the system ► Not the usual type of feedback in the body. E.g.: ▪ Positive feedback during childbirth ▪ Positive feedback during immune response to an infection ▪ Positive feedback during formation of blood clot POSITIVE FEEDBACK during childbirth POSITIVE FEEDBACK during childbirth ► The first contractions of labor (stimulus) push part of the fetus into the cervix, cervical stretching (controlled condition) increases ► Stretch-sensitive nerve cells (receptors) send more nerve impulses (input) to the brain (control center), which in turn releases the hormone oxytocin (output) into the blood ► Oxytoxin causes muscle in the wall of uterus (effector) to contract even more ► The contractions push the baby farther down the uterus, which stretches the cervix even more (response) ► The cycle of stretching and hormone release is interrupted only by the birth of the baby (cycle interruption) Other example.. THANK YOU