Anatomy Presentation Ho 1(introduction,cell)

Human Anatomy I Lecture For health officer students at AHSC By Habtamu Bayih (MD)

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Course description  The course is intended to give health officer students working knowledge of primarily gross anatomy, emphasizing the major systems that will be important in health centre activity including surgical and Obstetrics and Gynecology emergencies. Course objective  At the end of the course students will be able to:  List anatomical structures  Show their ability in surgery

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Anatomy Introduction Definition  It deals with the structure of human body  Anatomy means to cut up or dissect human cadavers  is the study of internal and external structures and the physical relationships among body parts Divisions of anatomy  microscopic anatomy  deals with structures that cannot be seen without magnification.  includes cytology and histology.  Cytology is the analysis of the internal structure of individual cells  Histology involves the examination of tissue  Gross anatomy or macroscopic anatomy  involves the examination of relatively large structures and features  usually visible with the unaided eye.

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 Surface anatomy  Is the study of general form and superficial markings.  Regional anatomy  focuses on the anatomical organization of specific areas of the body  such as the head, neck, or trunk.  Systemic anatomy  is the study of the structure of organ systems  such as the skeletal system or the muscular system.  Developmental anatomy  study of the complete devm’t of an individual from fertilization of an egg to death  Embryology  The study early developmental processes during the first 2 months 4

Levels of organization  Refers to the component parts of the human body  Helps to understand how the human body functions as a coordinated entity  From the smallest to largest there are six levels of organization 1.Chemicl level  Very basic level  Includes atoms and molecules  Atoms are the smallest stable units of matter  Molecules two or more atoms joined togather 2.Cellular level  Include cells formed from combination of molecules  cells are the smallest unit of structure capable of carrying out all life processes.  Although cells types differ in their structure and function, they have many characteristics in common.

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3.Tissue level  Is Collection of cells with similar structure and function plus  the extracellular substance located between them.  There are four basic types of tissues that make up the body  Nervous tissue  Connective tissue  Epithelial tissue  muscle tissue 4.Organ level  are composed of two or more tissue types  together perform one or more common functions.  The skin, stomach, eye, and heart are examples of organs.

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5.Organ system  is a group of organs classified as a unit  have a common function or set of functions.  Include the following the ff 11 systems • Support, motion, and shape • Integumentary  composed by skin, hair, nails, and sweat glands  protect, regulates temperature, prevent water loss, and  produces vitamin D precursors. • Skeletal  composed by bones, associated cartilage, and joints,protects  support, and allows body movement  produces blood cells and stores minerals.

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1. Muscular  composed by muscles attached to the skeleton  produces body movement, maintains posture, and  produces body heat. A. Circulatory systems and vascular integration 1. Cardiovascular  composed by heart, blood vessels, and blood  transport nutrients, waste products, gases, and hormones  plays a role in the immune response and  the regulation of the body temperature. 2. Lymphatic  composed by lymph vessels, lymph nodes, and other lymph organs  removes foreign substances from the blood and lymph,  combats diseases, maintains tissues fluid balance, and absorbs fats.

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• Neural and hormonal integration • Nervous  composed by brain, spinal cord, nerves and sensory receptors  is a major regulatory system.  It detects sensation, controls movements  control physiological and intellectual functions. • Endocrine  composed by endocrine glands such as the  pituitary,  thyroid, and  adrenal  participates in the regulations of the metabolism, reproduction,  and many other functions.

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• Body maintenance • Respiratory  composed by lungs and respiratory passages  exchanges gases between the blood and the air and  regulates blood pH. • Digestive  Compose by  mouth,  esophagus,  stomach,  intestines,and  accessory structures  performs the  mechanical and chemical processes of digestion,  absorption of nutrients, and  elimination of wastes.

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1. Urinary  composed by  kidneys  urinary bladder, and  ducts that carry urine  removes waste products from the circulatory system  regulates blood pH, ion balance, and water balance. • Reproductive, 1. composed by  gonads  accessory structures, and  genitals of males and females  perform the  processes of reproduction and  controls sexual functions and behaviors. 11

6.Organisimal level  An organism or any individual level  All the organ systems of the body work together to maintain life and health.  This brings us to the highest level of organization, that of the organism--in this case, a human being. Approaches to study 1.Anatomical Positions ( fig. 1)  In anatomy, description of any region or part of the human body assume that the body is in a specific position.  In the anatomical position, the subject:  Stands erect (up right position)  Facing the observer  With feet flat on the floor  Arms placed at the sides and  The palms turned for ward.

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Figure I.1. Anatomical position and regions of body.

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1. Body Regions  They designate particular area of the body  the principal regions are  Head consist of skull &face  Neck  Trunk consist of chest abdomen & pelvis  Upper limb  Lower limb

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• Directional Terms(f.g 1.2)  To locate various body structures in relation to one another, anatomists use certain directional terms to avoid the use of unnecessary words.  There are many pairs of directional terms with opposite meanings.  Superior- inferior  Anterior – posterior  Medial- lateral  Intermediate (b/n the two)  Ipsilateral – contra lateral  Proximal- Distal  Superficial- deep  Parietal- Visceral

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Fig. 1.2 Commonly Used Terms of Relationship and Comparison

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Commonly Used Terms of Relationship and Comparison Term

Meaning

Usage

Superior (cranial)

Nearer to head

Heart is superior to stomach

Inferior (caudal)

Nearer to feet

Stomach is inferior to heart

Anterior (ventral)

Nearer to front

Sternum is anterior to heart

Posterior (dorsal)

Nearer to back

Medial

Nearer to median plane

Lateral

Farther from median plane

Proximal

Nearer to trunk or point of origin (e.g., of a limb)

Distal Superficial

Farther from trunk or point of origin (e.g., of a limb) Nearer to or on surface

Deep

Farther from surface

Dorsum Palm

Dorsal surface of hand or foot Palmar surface of hand

Sole

Plantar surface of foot

Kidneys are posterior to intestine Fifth digit (little finger) is on medial side of hand First digit (thumb) is on lateral side of hand Elbow is proximal to wrist; proximal part of artery is its beginning Wrist is distal to elbow; distal part of lower limb is foot Muscles of arm are superficial to its bone (humerus) Humerus is deep to arm muscles Veins are visible in dorsum of hand Skin creases are visible on palm Skin is thick on sole of foot19

Terms of Movement  Various terms describe movements of the limbs and other parts of the body  Although most movements take place at joints where two or more bones or cartilages articulate with one another, several non-skeletal structures exhibit movement (e.g., tongue, lips, and eyelids).  Movements taking place at joints are described relative to  the axes around which the part of the body moves and  the plane in which the movement takes place  for example, flexion and extension of the shoulder take place in the sagittal plane around a frontal (coronal) axis.  Flexion  means bending of a part or decreasing the angle between body parts.  Extension  means straightening a part or increasing the angle between body parts.  Except for the thumb, flexion and extension movements are in the sagittal plane.

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 Abduction  means moving away from the median plane of the body in the frontal plane.

 Adduction  means moving toward the median plane of the body in the frontal (coronal) plane.  When referring to the digits (fingers and toes), abduction means spreading them, and adduction means drawing them together.

 Rotation  means moving a part of the body around its long axis.  Medial rotation turns the anterior surface medially, and 

lateral rotation turns this surface laterally.

 Circumduction  is the circular movement of the limbs, or parts of them, combining in sequence the movements of flexion, extension, abduction, and adduction.

 Pronation  is a medial rotation of the forearm and hand so that the palm faces posteriorly.

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 Supination  is a lateral rotation of the forearm and hand so that the palm faces anteriorly, as in the anatomical position.

 Eversion  means turning the sole of foot outward.  Inversion  means turning the sole of foot inward.

 Protrusion (protraction)  means to move the jaw anteriorly.

 Retrusion (retraction)  means to move the jaw posteriorly.

 Elevation  raises or moves a part superiorly.

 Depression  lowers or moves a part inferiorly.

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1. Planes And Sections(fig.1.3)  In order to visualize and study the structural arrangements of variousorgans, the body may be sectioned and diagramed according to planes of reference  Planes are imaginary flat surfaces that pass through the body parts  There are three fundamental plane 1. Sagittal - divides the body into right and left parts 1. Midsagittal – divides body into equal right and left halves 2. Parasagittal - divides body into unequal right and left 2. Frontal (Coronal)  divides the body into front and back (ventral and dorsal) sections 3. Horizontal (Cross, Transverse) divides the body into superior and inferior parts 4. Oblique plane passes through the body or organ at an angle between the

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Figure I.3. Planes of body

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1. Body Cavities  They are confined spaces within the body that contain internal organs.  The cavities help to protect, separate, and support the organs.  The various body cavities may be separated from each other by structures such as muscles, bones, or ligaments.  The two principal body cavities are: a) Dorsal body Cavity  is located near the dorsal (back) surface of the body & include  Cranial cavity formed by cranial bones & contains the brain  Vertebral (spinal) canal formed by vertebral column bone & contain spinal cord b) Ventral body cavity  located on the front aspect of the body.  A thin slippery tissue called a serous membrane lines the wall of the ventral cavity.  Include the following

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 Thoracic cavity(chest cavity)  Formed by the ribs,the muscles of the chest, the sternum,& thoracic portion of vertebral column  Within the thoracic cavity are  Two pleural cavities one around each lung  Pericardial cavity a fliud filled space that surrounds the heart  Mediastinum:  region between lungs from breastbone to back bone containing all structure with in the chest except the lungs.  Abdomino- pelvic cavity.  It is separated from the thoracic cavity by muscular Structure called diaphragm.  Extends from diaphram to the groin region  Abdominal cavity  stomach, spleen, liver, gallbladder, pancreas, small intestine

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 Pelvic cavity:  contains bladder and reproductive organs.  Other Body Cavities a. oral cavity (mouth) b. nasal cavity (sinuses for air passage) c. orbital cavities (eyes) d. middle ear cavities (in temporal bone) e. synovial cavities (freely moveable joints) Divisions of Abdominopelvic Cavity  A. Quadrants (from the umbilicus - belly button) 1. right upper quadrant (RUQ) 2. left upper quadrant (LUQ) 3. right lower quadrant (RLQ) 4. left lower quadrant (LLQ)

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 B. Regions (nine regions around umbilicus)  Right Hypochondriac

Epigastric

Left

 Right Lumbar

Umbilical

Left Lumbar

 Right Iliac

Hypogastric

Hypochondriac Left Iliac

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Cells  Two basic types of cells  Prokaryotic- bacteria Larger than eukaryotic cells Lacks a nucleus but has a nucleiod (a region of coiled DNA) DNA is in direct contact with rest of cells contents Cell wall- a rigid complex structure that protects the cell and helps to maintain its shape Some have a sticky outer coat called a capsule that further protects the cell and helps to adhere the cell to surfaces Some have projections  Pili- short projections that aid in adhesion  Flagella- used to propel through the liquid environment  Eukaryotic All other forms of life

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Stracture of a cell Three parts  Plasma (cell) membrane  the limiting membrane that separates the outer from the internal cell environment  Cytoplasm  all the cellular contents between the plasma membrane and the nucleus  Cytosol : the thick semifluid portion of the cytoplasm  Organelles  the highly organized structures in the cytoplasm that are specialized for particular functions. Organelles  Membranous organelles- surrounded by one or two layers of unit membrane •

Nucleus

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Mitochondria

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Lysosomes

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Peroxisomes

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Endoplasmic reticulum

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Golgi complex

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 Non membranous organelles- not membrane bound •Ribosome •Centrosome •Centrioles •Basal bodies Provides separate chemical environments for the various specialized reactions of the cell

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Nucleus •

largest structure in the cell

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called the control center because it contains the genetic material chromatin- loosely dispersed DNA associated with protein chromosomes- condensed DNA strands

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nuclear contents are bound by a membranous sac called a nuclear envelope (double layered membrane)

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studded with ribosomes- place of protein synthesis

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nuclear pores- provide communication with cytoplasm

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continuous with endoplasmic reticulum

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contains nucleolus- unenclosed area composed of protein, DNA, where ribosomes are manufactured

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Endoplasmic Reticulum •

a system of membranous flattened sacs (cisterns) dispersed throughout the cytoplasm

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Two types- Rough and smooth

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Rough endoplasmic reticulum  studded with ribosomes on the outer surface  makes more membrane and processes secretory proteins manufactured by the ribosomes  membrane continuous with the nuclear envelope

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Smooth endoplasmic reticulum  network of interconnected tubes void of ribosomes  continuous with rough ER  site of fatty acid, phospholipid, and steroid synthesis  in certain cells the enzymes within the smooth ER inactivates or detoxifies various chemicals (i.e., alcohol, pesticides, carcinogens)

Ribosome •

Small granules composed of ribosomal RNA and protein

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sites of protein synthesis

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are scattered throughout the cytoplasm and attached to ER

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Golgi Complex •

a system of stacked flattened sacs (cisterns) with expanded areas at their ends

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has golgi vesicles that cluster along the expanded edges of the cisterns

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is the “shipping and receiving” dock for newly synthesized lipids and proteins

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packages them into transport (secretory) vesicles that release the products to the external of the cell

Lysosomes •

membrane enclosed sacs formed the golgi complex that contains powerful digestive enzymes

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used to foreign substances and organisms

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digest old organelles (autophagy) for recycling

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capable of digesting the cell (autolysis)

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enzymes can also be used external to the cell in injury repair

Peroxisomes •

Resemble lysosomes but contain different enzymes 40

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kill bacteria, neutralize free radicals, breaks down fatty acids, and detoxify alcohol and other drugs.

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In the course of detoxification and the distruction of microorgansims , they produce hydrogen peroxide (H2O2)

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Contain catalase, an enzyme that breaks down hydrogen peroxide which is dangerous to the cell

Mitochondria •

The powerhouse of the cell because of it function in energy production

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Consist of two membranes  outer membrane- smooth  inner membrane- arranged in folds (cristae) where ATP is generated

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Center core called matrix

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Found throughout the cytoplasm of all cells, especially in cells that expend a lot of energy (i.e. muscle, liver..etc.)

Cytoskeleton •

A supportive meshwork of fine fibers that provide structural support for the cell

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three main types of fibers 41

1. microfilaments  helical rodlike globular protein (actin) structures involved in contraction in muscle cells and provide support, shape, and assist in locomotion in nonmuscular cells 2.

intermediate filaments  fibrous ropelike protein structures that serve as reinforcing rods for bearing tension and for anchoring certain organelles

3. Microtubules  straight hollow tubes composed of globular proteins called tubulins  provide anchorage of organelles and act as tracks along which organelles can move within the cytoplasm  guide the movement of chromosomes in cell division  the structural basis for flagella and cilia Cilia and Flagella •

Both consist of microtubules surrounded by cytosol and enclosed by plasma membrane

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Cilia- short numerous appendages used for locomotion and the movement of substances along the surface of the cell

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Flagella- longer, generally less numerous appendages used for locomotion (sperm)

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These motile appendages are constructed by basal bodies (kinetostomes), which also function as centrioles.

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The basal body is located at the base of each filament, anchoring it to the cell and controlling its movement.

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Cilia and flagella have the same structure. The only difference is that the flagella are longer.

Centrosome and Centrioles •

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Centrosome •

a dense area of cytoplasm near the nucleus

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is involved in mitosis

Centrioles •

a pair of structures composed of microtubules arranged in right angles that are located in the centrosomes.

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Has an unknown function in mitosis

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involved in the formation of flagella and cilia

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Plasma Membrane  Composed of two parallel rows of phospholipids called a phospholipid bilayer.  Contains two types of membrane proteins  integral- penetrate through the membrane  form channels that have pores through which certain substances move in and out of the cell.  transporters (carriers) that move substances from one side of the membrane to the other.  Receptors (recognition sites) which identify and attach various molecules (i.e. hormones, antibodies.. etc.).  cell identity markers-glycoproteins and glycolipids that enable the cell to recognize self and foreign.  peripheral - loosely attached to the exterior or interior surface of the membrane  Functions of the Plasma Membrane  Shape and protection  Communication- occurs via receptors and second messengers

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 Enzymes in the membrane break down signaling molecules to halt action  Signal Transduction Pathway (Second Messenger)  Maintains the electrochemical Gradient  Selective permeability- regulation of the entry and exit of materials

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