Introduction to Human Anatomy PDF

Lecture notes INTRODUCTION TO HUMAN ANATOMY BRAIN THY ROHo LUNGS HEART...

Lecture notes INTRODUCTION TO HUMAN ANATOMY BRAIN THY ROHo LUNGS HEART STOMACH UVER KIONEYS BLADDER INTESTINES By Dr /Abeer Madkour Mahmoud LECTURER OF HUMAN ANATOMY AND EMBRYOLOGY Faculty of Medicine South Valley University  Introduction to Human Anatomy Humananatomy is the study of the structure of the human body. For descriptrve purposes, the human body is divided into regions: head, neck, trunk, and limbs. The trunkissubdivided into the chest (thorax) and the abdomen. The abdomen is further subdividedintothe abdomen proper and the pelvis. Systemic anatomy is the study of the body s organ systems that work together to carry out complex functions. The basic systems are the skin, muscular system, skeletal system, nervous system, cardiac system, respiratory system, digestive system,etc. Anatomic Terminology Understanding the terms used for describing the structures in different regions of the students. hody is essential for The anatomical position: The anatomical position is the standard reference position of the body used to describethelocation of structures. In this position, Aperson is standing erect and facing forward, with the eyes looking forward, The upper limbs are by the sides, the palms of the hands are directed forward, The lower limbs are together, the soles of the feet are on the ground, and the toes are pointing forward Anatomical Planes: Four geometric planes are applied to the body in the anatomical position: -The median plane (midsagittal plane) is avertical plane passing through the center of the body, dividing it into equal right and left halves. 2.Asagittal plane (paramedian plane) is any vertical plane passing through the body parallel to the median plane. It divides the body into unequal right and left portions. 4. The coronal (frontal) plane is avertical plane situated at a right angle to the median plane. The coronal plane divides the body into anterior (front) and posterior (back) parts. 4- The horizontal (transverse) plane lies at right angles to both the median and the coronal planes. Ahorizontal plane divides the body into upper (superior) and lower (inferior) parts. 1  Median plane Median plane Coronal plane Superior Sagittal plano Prendoximof al upper limb Horizontal plane Latera border Posterior Anterior Dorsal surface Distal end of of hand Palmar surface upper of hand limb Medial border Horizontal and transverse planes Transverse Dorsal plane surface of foot Horizontal Plantar Inferior plane surtace of foot Anatomic terms used in relation to position. Note that the subjects are standing in the anatomical position. Terms of Position These terms describe the relationship of parts of the body or compare the position of two structures relative to each other. Median: refers to any structure lying in the median plane. Medial: refers to a structure situated nearer to the median plane of the body than another. Lateral: refers to a structure that lies farther away from the median plane than another. For example, the thumb is lateral to the little finger. Anterior (ventral) surface: describe the position of structures nearer to the "front" of the body. Posterior (dorsal) surface: describe the position of structures nearer to the "back" of the body. 2  In describing the hand, the terms palmar and dorsal surfaces are usedin place of anterior and posterior, respectively. In descrlblng the toot, the term plantar surtace refers tothe sole of the foot and dorsal surface surface. indlcates the upper (top) Proximal: refers to astructure nearer to the attachment of alimb. Distal: refers to a structure farther from the attachment of a limb. (e.g,, in the unper limb, the shoulder is proximal to the elbow, and the hand is distal to the elbow). Superior: refers to a structure that is nearer tothe vertex of the skull..Inferior: refers to astructure that is situated nearer the sole of the foot. Superficial::refers to a structure closer to the surface of the body.. Deep: refers to astructure farther away from the surface of the body. (e.8., the skinis superficial Ito the ribs, but the heart is deep to the ribs). , The terms internal and external are used to describe locations relative to the center of a structure or space. Internal is inside the structure and external is outside the structure. Iosilateral: refers to structures on the same side of the body (e.g. the right thumb and right big toe are ipsilateral). Contralateral: refers to structure on the opposite side of the body relative to another structure (e.g. the right hand is contralateral to the left hand).. The supine position of the body is lying on the back.. The prone position is laying face downward. Terms Related to Movement: In the musculoskeletal system, movement takes place at joints..Flexion indicates bending or decreasing the angle between the bones or parts of the body occurring in a sagittal plane. For joints above the knee, flexion involves movement in an anterior direction..Extension indicates straightening or increasing the angle between the bones or parts of the body. Extension usually occurs in a sagittal plane. "Lateral flexion refers to a lateral bending movement of the trunk in the coronal plane. "Dorsiflexion describes the movement of the foot with flexion at the ankle joint (lifting the top of the foot superiorly). 3  Abduction Of shoulder Adduction Extension Flexion Of shoulder joint Of hip joint Abduction Flexion Adduction Flexion Of knee joint Of elbow joint Extension Extension Medial rotation Circurnduction of shoulder joint of shoulder joint Lateral rotlation of shoulder joint Some anatomic terms used in relation to movement. 4  Laleral flexion of trunk Aupinalion of foroarm Pronalion of lorearm Invarslon ol lold Everaion of loolooduction ot tingors o rAbductlon of lingors mora o ossl, soolsrluto n o Adduction of thumb Opposition of thumb and ittle finger Floxion of thumb Abduclion of thunb Extenslon of thumb Some anatomic terms used in relation to movement. "Plantar flexlon describes the movement of the foot with moving the sole of the foot inferlorly, as in standing on the toes. "Abduction is movement away from the midline of the body in the coronal plane (e.g., when moving an upper limb laterally away from the side of the body). "Adduction is movement toward the midline of the body in the coronal plane (e.g., when moving an upper limb toward the side of the body). 5  adduction movements generally occur in a coronal plane N.B: Abduction and an anteroposterior axis. In the fingers and toes, abduction is applied to the arround apart of the digits, and structures. adduction is applied to the drawing together spreaditheseng of "Inversion is the movement of the sole of the foot toward the (facing the sole medially). median plane "Eversion is the opposite movement of the sole of the foot away from the plane, turning the sole laterally. median.Rotation is the term applied to the movement of a part of the body around is. long axis: Medial (internal) rotation is the movement that brings the anterior surface of a limb closer to the median plane, and lateral (external) rotation is the movement that takes the anterior surface away from the median plane facing laterally..Circumduction is a circular movement that involves sequential abduction, extension, and adduction (as in the shoulder and hip joints). flexion,.Pronation of the forearm: medial rotation of the forearm in such a manner that the palm of the hand faces posteriorly. When the elbow joint is flexed, pronation moves the hand so that the palm faces inferiorly. "Supination of the forearm lateral rotation of the forearm from the pronated position so that the palm of the hand comes to face joint is flexed, supination moves the hand so that anteriorly. When the elbow the palm faces superiorly. 6  The Skin The skin provides: Protectlon of the body from environmental effects, such as ultraviolet radiation and invading microorganisms. Containment for the body's structures (e.g., tissues and organs). Thermal regulation. oSensation (e.g-, pain) by way of superficial nerves and their sensory endings. Synthesis and storage of vitamin D. The skin is the largest organ in the body. It is divided into two parts: the superficial aart. the epidermis,and the deep part, the dermis. The epidermis is akeratinized stratified epithelium that provides aprotective outer surface. The epidermis has no blood vessels or lymphatics. The avascular epidermis is nourished by the underlying vascularized dermis, On the palms of the hands and the soles of the feet, the epidermis is extremely thick to withstand the wear and tear that occurs in these regions. In other areas of the body,such as on the anterior surface of the arm and forearm, it is thin. The dermis is composed of dense connective tissue containing many blood vessels, vmphatic vessels, collagen and elastic fibers, and nerves. The collagen and elastic fibers provide skin tone and account for the strength and toughness of skin. The bundles of collagen fibers in the dermis run in all directions to produce a tough felt like tissue, in any specific location most fibers run in the same direction determining the characteristic tension and wrinkle lines in the skin, this is called tension ines (cleavage lines or Langer lines) tend to run longitudinaly in the limbs and run transversely in the neck and trunk. The dermis of the skin is connected to the underlying deep fascia or bones by the superficial fascia. N.8.. The elastic fibers of the dermis deteriorate with age and are not replaced, consequently, in older people, the skin wrinkles and sags as it loses its elasticity. The appendages of the skin: They are the nails, hair follicles, sebaceous glands, and sweat glands. * The nails are keratinized plates on the dorsal surfaces of the tips of the fingers and toes. The proximal edge of the plate is the root of the nail. Except 7  folds for the distal edge of the plate, the nail is surrounded and overlapped by covered by the nail is the nail SN Known as nail folds. The surface of skin bed. cao uns esi Shaft of hair Epider Plexus General structure of the skin of arteries and its relationship to the and veins i superficial fascia. Note that SebaceoUS -Dermis hair folicles extend into the gland deeper part of the dermis or Hair tollicle into the superficial fascia, Arrector pil1 whereas sweat glands musclo extend deeply into the Plexus superficial fascia. of arteries 10 2ig S and veins brs Superficial fascia Hair bulb Body of eccrine sweat gland o oold vspsoait Dudt of occrine sweat gland CROSS-SECTION DORSAL VIEW Lateral nail groove Distal edge Lateral of nail plale nal fold Lateral nad folds (paronychum) Lunula Nal plate Epidermis Dstal phalanx Cubde (eponychium) SAGITTAL VIEW A diagram showing the Proximal. nal fold Nal bed relationship of the nail to Nadl plate Cuuce (eponychium) other structures of the Myponychium finger. Epidermis fibers Nal Distal phaian  Hairs grow out of follicles, which are invaginations of the dermis. The deep part of the hair follicles is called hair bulbs, epidermis into the deeper part of the dermis and its concavity is occupied by penetrate to the tissue calledthe hair papilla. Aband of smooth muscle, the vascular connective the undersurface of the follicle to the superficial part of the arrector pili, connects innervated by sympathetic nerve dermis. The fibers, and its contraction muscle is move into a more vertical position; it also causes the hair to compressesthe causes it to extrude some of its secretion. sebaceous gland and Hairs are distributed over the whole surface of the body, except on the lips, the palms of the hands, the sides of the fingers, the glans penis and minora and the internal surface of the labia majora, and thee clitoris, the labia feet and the sides of the toes. soles and sides of the sebaceous glands secrete an oily material (sebum) onto the shafts of the hairs as they pass up through the necks of the tollicles. They are situated on the sloping undersurface of the follicles and lie within the dermis. Sebum is that heloe preserve the flexibility of the emerging hair. Sweat glands are long, spiral, tubular glands distributed over the surface of the hody, except on the red margins of the lips, the nail beds, and the glans penis and clitoris. Fascia Fascia is the connective tissue that encloses the body deep to the skin. The fasciae of the body can be divided into two types, superficial and deep. " The superficial fascia, or subcutaneous tissue, is a mixture of loose areolar and adipose tissue that unites the dermis of the skin to the underlying deep fascia. It is thick in the scalp, the back of the neck, the palms of the hands, and the soles of the feet, where it contains numerous bundles of collagen fibers. Contents of the superficial fascia: 1- Fat: The thickness of the superficial fascia varies with the amount of fat in it. Its distribution and amount vary in both sexes. In the eyelids, auricle of the ear, penis and scrotum, and clitoris, it is devoid of fat. 2- Muscles e.g. platysma muscle in the neck, and dartos muscle in the scrotum. 3- Mammary gland in the pectoral region.  4 Blood vessels, lymph vessels, and nerves. Ine deep fascia isa dense, inelastic membranous layer of connective tissue. t attached to the deep surface of the superficial fascia, and often ensneatnes muscles and divides them into functional groupings. Extensions of the deep fascia may attach to the skeleton, forming the intermuscular septa. In the thorax and abdomen, it is avery thin fim of areolar tissue covering the muscles and aponeuroses. The deep fascia at the wrists and ankles is thickened to form retinacula which holdthe tendons in place. Biceps Musculocutaneous nerve Median nerve Cephaic vein Humerus Brachial artery. Brachialis Ulnar nerve. Lateral intermuscular Medial septum intermuscular, septum Coracobrachialis Radial nerve Deep fascia Triceps Superficial fascia' Skin Section through the middle of the right arm showing the arrangement of the superficial and deep fascia. Note how deep extensions of the deep fascia extend between groups of muscles and form intermuscular septa, which divide the arm into fascial compartments. 10  Bone specialized, hard form of connective tissue that tissue.itt is a highly Bone is aliving of the skeleton. It is often stated that there are 206 bones in the makes up most adult skeleton provide: skeleton. Bones of the its vital cavities. Support for the body and for vital structures (e.g., the heart and brain). Protection movement (leverage). The mechanical basis for calcium). Storage for salts (e.g., of new blood cells (produced by the marrow in the A continuous supply medullary cavity of many bones). is a dense fibrous connective tissue surrounding the bones and The periosteum bones The the surfaces of bones, except where they articulate with other rovering aspects of the bones. It is capable of layíng down periosteum nourishes the external bone (particularly during fracture healing) and give attachment to tendons and more ligaments. Classification of Bones A-Regional classification: organized into two main groups: the axial In the regional classification, the bones are and appendicular skeletons. supporting axis of the body 1- The axial skeleton consists of the central vertebral column including the skull, vertebral column, ribs, and sternum. The of fibrocartilage consists of a chain of 33 vertebrae with intervertebral discs groups: 7 cervical between most of them. The vertebrae are divided into five vertebrae in vertebrae in the neck, 12 thoracic vertebrae in the chest, 5 lumbar coccygeal the lower back, 5 sacral vertebrae at the base of the spine, and 4 tiny vertebrae. limb and 2- The appendicular skeleton includes the bones of the upper The shoulder (pectoral) girdle, and bones of the lower limb and pelvic girdle. shoulder girdle consists of the clavicle and scapula, whereas the pelvic girdle consists of the hip bones. The shoulder girdle and the pelvic girdle provide connection points between Each the appendicular and the axial skeletons for the mechanical load transfer. of the upper and lower limbs consist of three segments (proximal, intermediate and distal). 11  upper andlowerlimbs: Table describing the bones forming the Lower limb Upper limb Femur Proximal segment Humerus Tibia (medially) Intermediate segment Ulna (medially) Fibula (laterally) Radius (laterally) foot consists of: The hand consists of: The Distal segment 7tarsal bones 8 carpal bones 5 metatarsal bones 5 metacarpal bones Phalanges of the Phalanges of the toes (each consist fingers (each consist of 3 of 3 phalanges phalanges except except the big toe) the thumb) B- According to the structure: Bone is found in two forms: superficial layer of 1- Compact bone: is dense mass of bone and forms the bone and the tubular shafts of the long bones. It provides strength. branching 2- Cancellous bone (spongy or trabecular): is a less dense and fills the network of bone trabecula, it occurs in the ends of long bones are filled with a flat and irregular bones; the spaces between the spicules highly vascular bone marrow. C- According to the general shape: Bones are classified according to their shape into 1- Long bones (e.g., the humerus in the arm). carpus 2- Short bones are cuboidal and are found only in the tarsus (ankle) and (wrist). 3- Flat bones e.g. the sternum, scapula, and vault of the skull. of the face. 4- Irregular bones e.g., the vertebrae, hip bones and the bones 5- Sesamoid bones (e.g., the patella or knee-cap) develop in certain tendons and are found where tendons cross the ends of long bones in the limbs. The function of a sesamoid bone is to reduce friction on the tendon; it can also alter the direction of pull of a tendon 6- Pneumatic bones of the skull contain air spaces (paranasal sinuses). 12  D-According to their development and ossification: Bones deevelop in one of the following two ways: 1- Intramembranous ossification (membranous bone formation): This is the process of bone formation in connective tissue and mesenchymal models of bones form during the embryonic period. Most flat bones develop in this way by direct calcium deposition into a mesenchymalmodel. 2. Endochondral ossification (cartilaginous bone formation): Cartilage models of the bones form from mesenchyme during the fetal period, and bone subsequently replaces most of the cartilage. Most long and irregularly shaped bones develop by calcium deposition into a cartilaginous model of the bone. Frontal bone Parnatal bone Naxdla Occapital bone SAu. Mandble landible. davicde Clavide Pectoral Scapuls Scapula girdie Stemum Humerus Thoræoc Rbs ca Costal cartileges Vertebral colunn Petvis Hp bone Sacrum Ulna. Coccyx -Radus Carpus Metacapal bones Phalanges Femur Patea Fibula Tibia letatarsal bones Tarsus Phalanges (a) Anterior view (b) Posterior view The Adult Skeleton. The appendicular skeleton is colored green, and the rest is the axial skeleton. 13  ntr b em Doterket ve Afas (Cti As (C2) Cerat vtre Long bone Fiat hrs dumer parintat, C Thorscie veebrae Irregdar ben Shorl bones enetes carpals 12 Semoid bn Lunbar verebras patellay Bone Classification Based on Shape Sacrum -S5 Coccy Cocryn The vertebral column (Anterior view, posterior view) N.B: Long bones are found in the limbs (e.g.. the humerus, femur, metacarpals, metatarsals, and phalanges). They have a tubular shaft, the diaphysis, and usually an epiphysis at each end. During the growing phase, the diaphysis is separated from the epiphysis by an epiphyseal plate. The part of the diaphysis that joins the epiphysis and epiphysial plate is called the metaphysis. The shaft has a central marrow cavity containing bone marrow. The outer part of the shaft is composed of compact bone that is covered by periosteum. The ends of long bones are composed of cancellous bone surrounded by a thin layer of compact bone. The articular surfaces of the ends of the bones are covered by hyaline cartilage. 14  Epiphyslal artery Periosteum Secondary Ossification Center Primary (epiphysis) ossification center |(diaphysis) -Epiphysial plate Periosteal bud Diaphysis Cartlage -Epiphysial plate long -Melaphysis Development and growth of a primany bone. A. The formation of Nutrient artery - centers and secondary ossification occurs on is (derived from periosteal bud) Secondary ossification chown. B. Growth in length KA) Center cartilaginous (epiphysis) both sides of the epiphysial plates (double-headed from the arrows). The bone formed does primary center in the diaphysis from the -Epiphysis not fuse with that formed secondary centers in the epiphyses size. Epiphysial plate adult until the bone reaches its When growth ceases, epiphysial plate bone-to-bone fusion. is replaced by a -Diaphysis -Metaphysis Epiphysial plate (B) Epiphysis Joints Joints (articulations) are unions or junctions between two or more bones or rieid parts of the skeleton. Joints exhibit avariety of forms and functions. Types of Joints Joints are classified into one of the following three types: Fibrous joint (synarthrosis): bones joined by fibrous connective tissue. Subtypes are; 15  The articulating surfaces of the bones are tightly linked by fibrous - Suture: that fills the joint space. The example of this subtype is sutures of the tissue vault of the skull. unites the bones with asheet of ii- Syndesmosis: It is a type of fibrous joint membrane. This type of joint fibrous tissue, either a ligament or a fibrous the interosseous allows for little movement. Examples of this type are radius and membrane in the forearm (a sheet of fibrous tissue that joins the ulna) and the inferior tibiofibular joint. the socket ii- Gomphosis: it is an aticulation between the root of the tooth and in the alveolar process of the jaw. babaod-psscla lsirdck Suture lune -Suture UIna Syndesmosis Radiusydolae Dense Root of Socket fibrous tooth Antebrachial connective Gomphosis tissue interosseous membrane Perlodonta ligament (a (b) (c) Fibrous joints (a: Suture, b: Syndesmosis, c: Gomphosis) Cartilaginous joint lamphiarthrosis): Bones are joined by cartilage, or by cartilage and fibrous tissue. It includes -Primary cartilaginous (synchondrosis) joints: The bony ends (articular surfaces) are fused by hyaline cartilage. Example is the epiphysial plate of the growing long bones connecting the diaphysis with the epiphysis. Primary cartilaginous joints permit growth in the length of a bone. When full growth is achieved, the epiphysial plate converts to bone and the epiphyses fuse with the diaphysis. Secondary cartilaginous (symphysis) joints: The articular surfaces are lined by hyaline cartilage with an intervening fibrocartilaginous disc. Joints of this type of are strong,slightly movable united by fibrocartilage. They are located along the midline 16  according multiaxial SYNOHONDROSES orSynoviallubricates lines margins surrounded The The I|- andSynovial vertebral cartilapeCastal of exampleHinge:movement. of Plane the cavity articular are the the joints to of separated fibrous the bodies, body. movement), as scapula(gliding): their one of by These is articular the surfaces cartilage) (hyaline generally articular a joints Epiphyseal piate Examples the shape capsule. fibrous Examples joint by diagram A Long bone -CostosternalSternum the and synchondrosis elbow are manubriosternal surfaces. (diarthroses): a of uniaxial the The and surface is capsule. joint the showing of are follows: the allow Synovial lined joint. clavicle), articular this cavitybones the type to by joints for typeare acromioclavicular of fluidthose a filled are types and surfaces considerable synovial joint, 17 movement covered This M permittingjoints is of with of produced the is the SYMPHYSES and the are the between membrane, other, a cartilaginous small by intervertebral the flat. that most flexion movement a Vertebral disk symphysis byalso, amount thin common joint It they the only the thewhich layer (between andcarpal bones. permit synovial joints allows and synovial of oftype publsjoints extension extends synovial (uniaxial, hyaline thsimple e aremembrane, of sympysis Pubio between membrane joints. only. acromion classified fluid from cartilage gliding biaxial, the and the An it  central axis. In these Pivot joints: are uniaxial ioints permit rotation around a Examples are joints, a rounded process of bone rotates within a sleeve or ring. around the median atlanto-axial joint (in which the atlas (C1 vertebra) rotates rotation of the afinger-like process, the dens of the axis (C2 vertebra), during head) and the superior radioulnar joint. iv- Saddle: The opposing articular surfaces are shaped like a saddle on the horse's back (i.e., they are reciprocally concave and convex). These are biaxial joints (movements occurring around two axes at right angles to each other) permitting flexion, extension, abduction, and adduction. The example is carpo metacarpal joint at the base of the thumb. V Condyloid joints: Condyloid joints are biaxial permitting flexion and extension as well as abduction and adduction. The metacarpo-phalangeal joints (knuckle joints) are condyloid joints. vi Ball and socket joints: These are multiaxial joints allow movement in multiple axes and planes: flexion and extension, abduction and adduction, medial and lateral rotation, and circumduction. Examples are the hip joint and the shoulder joint. vij- Ellipsoid joint: An elliptical convex articular surface fits into an elliptical concave articular surface. Mainly biaxial movements are allowed (flexion, extension, adduction and abduction). Example is the radiocarpal (wrist) joint. beud Bone Structure of the synovial joint Synovial mermbrane Articular Articular cartlage capsuie Joint cavty Bone containig synovial fluid 18  -Clavicle Plane Plane ants (usuaty unianal) permit giirg o Acromien Dens of scapula srhng menmerts Allas(C1) Acromioclavicular Axis (C2) joint Allanto-axlal jolnt Plvot Humerus Minge In pivol joints Hinge joints (uniaxial), a Radius (uniaxiai) permit rounded process flezion and of bone fits etension orty into a bony ligamentous Ulna soCkel, permitting rotation. Elbow jolnt baut Acetabulum of hip bone Head of Trapezium lemur -Firstu)M metacarpal Saddle In saddle joints (biaxial), saddle shaped heads Hip Joint permit movement otJ3o Corpometacarpal in two different Ball and socketl joint planes. In ball and socket nulov) joints (multiaxial), a rounded head fits into a concavity, permitting Melacarpal o bosoiiel movement on several axes. oltsro Proximal Condyloid phalanx Condyloid joints (biaxial) lozzsy bot ttiv63 permlt lexion and extension, abduction and adduction, and circumduction. 36bws bes Metacarpophalangeala COnjolnt eleusn isislol2 - Types of the synovial joints Joint Stability ortto brs The stability of a joint depends on three main factors: A- The morphology of the bony articular surfaces,, 66 hoelar dSnsotes B- The ligaments, and C- The tone of the muscles around the joint. WEY sbruovsoh go 19  Fibularis longus musclo holclie. Hemiaphorical Cup-shaped Cruclate up latoral longiludinal aroh head of temur acetabulum of right toot ligamonts Fibularis lendon Madial collateral ligament Arch of foot Hip joint Knoo joint C Factors affecting the joint stability A. Shape of articular surfaces. B. Ligaments.C. Muscle tone. Muscles Muscle cells (muscle fibers) are specialized contractile cells. They are organized into tissues that move body parts or temporarily alter the shape of internal organs. Associated connective tissueconveys nerve fibers and capillaries to the muscle cells as it binds them into bundles or fascicles. Three types of muscle are described based on distinct characteristics relating to whether it is normally willfully controlled (voluntary or involuntary). whether it appears striped or unstriped when viewed under a microscope (striated or smooth). whether it is located in the body wall and limbs (somatic) or makes up the holloworgans (viscera, e.g., the heart) of the body cavities or blood vessels (somatic or visceral). The three types of muscle are skeletal, smooth,and cardiac. |- Skeletal muscle It is astriated voluntary somatic muscle that makes up the gross skeletal muscles that compose the muscular system, moving or stabilizing bones and other structures. A skeletal muscie has two or more attachments. The more proximal, less mobile attachment is referred to as the origin. The more distal, more mobile attachment is the insertion. When a muscle contracts, the insertion is drawn proximally toward the origin. However, under varying circumstances, the degree of mobility of the attachments may be reversed (or interchanged). 20  to The fleshy part of the muscle is referred as its belly. The ends of a muscle are attached to supporting elements (bones, (O Origin cartilage, ligaments, or other muscles) by cords of fibrous tissue called tendons. Some tendons (e.g., those belonging to the flat, Bolly wide abdominal oblique muscles) form a Gastrocnemius thin, strong sheet termed an aponeurosis. Other tendons may form a raphe, which is an interdigitation of the tendinous ends of Insertion fibers of flat muscles. Origin, insertion, and belly of the gastrocnemius muscle. Circular Convergent Multipennate Fusiform Common tendon lor the insortion Erternai oblique aponeurosis of the gastrocnerius and Parallel soleus muscles Bipennate Unipennate Raphe of mylohyoid muscles The architecture and shape of a skeletal muscle Examples of (A)a tendon, (B)an aponeurosis, and (C) a raphe. depend on the arrangement of its fibers. 21 Forms of the skeletal muscles: Accordlng to the arrangement of muscle fibers 1- Parallel form: the muscle fibers run parallel to the axis of force generation. this includes varleties a- Fusiform: muscle that has a wide center and tapered ends (e.g. biceps brachii). b- Strap: long. flat muscle fibers are parallel from origin to insertion (e.g. sartorius). c Convergent (triangular or fan-shaped): muscle fibers are fanned out broadly at the origin and converge at its insertion (e.g. pectoralis major). d- Circular muscle: in which the fibers are longitudinally arranged, but create a circle from origin to insertion (e.g. the orbicularis oculi). 2- Pennate form: in which the muscle has a feathered appearance where the muscle fibers run obliquely to the line of pull. Varieties are; Unipennate: the tendon lies along one side of the musce,and the muscle fibers pass obliquely to it (e.g., extensor digitorum longus), b- Bipennate: the tendon lies in the center of the muscle,and the muscle fibers pass to it from twosides (e.g., rectus femoris). c- Multipennate: It is as a series of bipennate muscles lying alongside one another (e.g., the deltoid). d- Circumpennate: Muscles have the tendon lying within its center and the muscle fibers passing to it from all sides, converging as they go (e.g., tibialis anterior). Skeletal Muscle Action All movements are the result of the coordinated action of many muscles. Muscle contraction that produces movements can act in several ways: 1- Agonist (prime mover): Amuscle is an agonist (prime mover) when it is the chief muscle or member of a chief group of muscles responsible for producing a particular movement. 2- Antagonist: Itthe muscle that opposes the action of the agonist muscle. 3- Fixator: A fixator muscle contracts to stabilize the origin of the prime mover so that it can act efficiently. 4- Synergist: It may directly or indirectly assist a prime mover during movement. I|-Cardiac muscle Cardiac muscle consists of involuntary partially striated muscle fibers that branch and unite with each other. It forms the myocardium of the heart. Its fibers tend to be arranged in whorls and spirals, and they have the property of spontaneous and rhythmic contraction. Specialized cardiac muscle fibers form the conducting system 22  Right Right four The cells. and thebody's Blood The spindle-shaped the af following plasma. (1) (2) cardiovascular " " " Smooth nodes the chambers; heart ventricle: atrium: is tissues capillaries, The and The Inpropels In In propelling In heart. the storage the the is fluid a blood intoheart, of superior a The walls tubes muscle he tCardiac pulmonary receives righthollow elements: and the the digestive receives which organs the cells conducting blood connectivevenules,vessels then systemic system of contents the contents closelyof is and atrium, the muscular the a muscle carries returns platelets, pumps blood such system, the circulation inferior and that consists by non-striated deoxygenated right tissue circulation Cardiovascular System body system is blood veins. as the through arranged organ nutrients, to carry blood vessels. the III-Smooth Muscle supplied venae ventricle, peristaltic it (as Heart The white the that of and via from urinary mixes the in heart the tointo the the in involuntary 23 circulates bundles in by cavae. blood the oxygen, blood ureters), lumen. the pulmonary e th left blood, supply the bladder ingested autonomic middle through pulmonary contractions. right fromatrium, cells the or myocardium. and through including sheets. itvisceral waste the body and food provides trunkatrium mediastinum. the (WBCs), nerve and the systemic veins. circulation tissues; with It left products the the uterus. muscle is and and the present fibers The red arteries digestive pulmonarypumps ventricle. blood arteries, and circulation It for motive consists that is to blood in; to gas terminate it divided and cells consists juices power from reach arterioles, exchange of arteries. into via (RBCs) long, the the into the the and for in of  Left atrium: receives the Oxygenated blood from the lungs via pulmonary veins (a andleft pulmonary veins). veins: upper right and left, and lower right Left ventricle: receives the blood from the left atrium and pumps it into the systemic clrculatlon vla the aorta. chambers. The interatrial Two internal septa divide the heart into its four separates the right and left atria, whereas the interventricular septum separates the septum right and left ventricles. The heart has an apex, a base, 4 surfaces, and 4 borders. downwarde The apex: it is formed only by the left ventricle and is directed fonwards and to the left. Pulsations of the apex can be felt below nipple of the left breast, in the left sth intercostal space at the midclavicular line. Base: It is formed mainly by the left atrium and the back of the right atrium. It is directed backwards and to the right. It lies opposite the thoracic vertebrae (T6 T9). Aorta Superior -Ligamentum arteriosum vena cava Right -Left pulmonary artery pulmonary -Pulmonary trunk artery -Left atrium Right puimonary Left veins pulmonary veins -Left ventricle (Left border) Right atrium (Right border) Right ventricle lnterior vena cava Apex Sternocostal (anterior) view of the heart The surfaces: 1-Anterior (sternocostal) surface: It is directed forwards, upwards and to the left, related to sternum and ribs. 2-Diaphragmatic surface: It is directed downwards and slightly backwards related to the diaphragm. It is formed primarily by the left ventricle. 3-Right pulmonary surface: formed mainly by the right atrium. 4-Left pulmonary surface: formed mainly by the left ventricle. 2  The borders: the two atria, mainly the left. 1-Upper border: It is formed by by the right atrium. 2-Right border: It is formed only ventricle and the apical part of left ventricle. right -lower border: It is formed by the ventricle and partly by the left atrium. mainly by the left 4-Left border: It is formed Left recurrent laryngeal nerve Left common Arch of Ligamentum arteriosum carotid artery aorta Left subclavian artery Bifurcation of puimonary trunk Superior vena cava Right atrium Pulmonary veins Left atrium Left ventricle Inferior vena cava Coronary sinus Base of the heart Interventricular Aortic semilunar septum valve Tricuspid AV valve Bicuspid AV valve (mitral valve) Valve leaflet Valve leaflet Chordae tendineae Chordae tendineae Papillary muscle Papillary muscle -Trabeculae carneae Septomarginal trabecula (moderator band) Internal features of the heart There are 3 main sulci (grooves): Coronary (atrioventricular) and the anterior and posterior interventricular grooves (sulci) that course on the surfaces of the heart: they contain the major vessels of the heart and epicardial fat. 25  andThe Valves The of are The portion N.B. semilunar Aortic 4- 3-atriaright atria 2- 1- three Vessels The Blood The 5- 4- 3- 2- 1- the Conducting 3. 2. 1. Pulmonary MitralTricuspid responsible conducting conducting when side > > blood Atrioventricular Atrioventricular The The Sino-atrial Thepericardium. Endocardium: Myocardium serous heart Epicardium of Veins, Arteries,types atria of atrioventricular and (bicuspid) the the vesselssubendocardial the atrial of and valve: which heart mitral wall semilunarventriclesventricles heart: whichblood ventricles, system node for system system portion makes has valve: It are initiation has (cardiac ventricle.valve. rightallows on lefttheventricle. transport lines three vessels: transport bundle node(SAN). a is of ofthick of contract. the are closed bundle formed th e th e up valve: between It plexus and the the left deoxygenated (AVN). muscle) lavers: th e separated allows blood blood (AVB). and walls.heart inner blood network maintenance heart heart: pulmonary trunk. between side) branches, ofand of: coordination external the toward conduction consists surface has is that Oxygenated away the left by 26 of relatively primary layer. ventricle prevent the atrioventricular the from tubes of and of right heart. cells of the mnodified forms t blood passto the that the thin constituent is the cardiac ventricle and (the formed to heart.transport contraction walls, the blood Purkinje th e atriumto pass thefromto rhythm. cardiac internal opening and valves whereas by from rightthe from atrium of the muscle the fibers). of layer the the refluxing (tricuspid the blood. the middle visceral opening of the of the left musculaturefibers There ventricular the aorta. layer. layer into on which heart. of are the the the of  of decreasing Arteries Arteries circulation Typestheof 2- 1- the arteries. wall bloodfibers. 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