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First Semester: ANATOMY & PHYSIOLOGY
LESSON 1: THE HUMAN BODY - AN ORIENTATION
ANATOMY – study of the structure and shape of the body and its parts PHYSIOLOGY - study of how the body and its parts work or function
ANATOMY – Levels of Study: Gross anatomy - Large structures & easily observable Microscopic anatomy
- Structures cannot be seen with the naked eye.
- structures can only be viewed with a microscope Integumentary
- Forms the external body covering
- Protects deeper tissue from injury
- Helps regulate body temperature
- Location of cutaneous nerve receptors
Skeletal
- Protects and supports body organs
- Provides muscle attachment for movement
- Site of blood cell formation
- Stores minerals
Muscular
- Produces movement
- Maintains posture
- Produces heat
Nervous
- Fast-acting control system
- Responds to internal and external change
- Activates muscles and glands
Endocrine
- Secretes regulatory hormones
- Growth
- Reproduction
- Metabolism
Cardiovascular
- Transports materials in body via blood pumped by heart
- Oxygen
- Carbon dioxide
- Nutrients
- Wastes
Lymphatic
- Returns fluids to blood vessels
- Cleanses the blood
- Involved in immunity
Respiratory
- Keeps blood supplied with oxygen
- Removes carbon dioxide
Digestive
- Breaks down food
- Allows for nutrient absorption into blood
- Eliminates indigestible material as feces
Urinary
- Eliminates nitrogenous wastes
- Maintains acid-base balance
- Regulates water and electrolytes
Reproductive
- Produces offspring
- Testes produce sperm and male hormone
- Ovaries produce eggs and female hormones
NECESSARY LIFE FUNCTIONS
- Maintain boundaries
- Movement
- Locomotion
- Movement of substances
- Responsiveness
- Ability to sense changes and react
- Digestion
- Breakdown and absorption of nutrients
- Metabolism —chemical reactions within the body
- Break down complex molecules into smaller ones
- Build larger molecules from smaller ones
- Produces energy
- Regulated by hormones
- Excretion
- Eliminates waste from metabolic reactions
- Wastes may be removed in urine or feces
- Reproduction
- Occurs on cellular level or organismal level
- Produces future generation
- Growth
- Increases cell size and number of cells
SURVIVAL NEEDS
- Nutrients
- Chemicals for energy and cell building
- Includes carbohydrates, proteins, lipids, vitamins, and minerals
- Oxygen
- Required for chemical reactions
- Water
- 60 to 80 percent of body weight
- Most abundant chemical in the human body
- Provides for metabolic reaction
- Stable body temperature
- Atmospheric pressure
- Must be appropriate for gas exchange
HOMEOSTASIS
maintenance of a stable internal environment
- A dynamic state of equilibrium
- Necessary for normal body functioning and to sustain life Homeostatic imbalance
- A disturbance in homeostasis resulting in disease
THE LANGUAGE OF ANATOMY
- Special terminology is used to prevent misunderstanding
- Exact terms are used for
- Position
- Direction
- Regions
- Structures
DIRECTIONAL TERMS
- Superior (cranial or cephalad): toward the head end or upper part of a structure or the body; above
- Inferior (caudal): away from the head end or toward the lower part of a structure or the body; below
- Ventral (anterior): toward or at the front of the body; in front of
- Dorsal (posterior): toward or at the backside of the body; behind
- Medial: toward or at the midline of the body; on the inner side of
- Lateral: away from the midline of the body; on the outer side of
- Intermediate: between a more medial and a more lateral structure.
- Proximal: close to the origin of the body part or point of attachment to a limb to the body trunk
- Distal: farther from the origin of a body part or the point of attachment of a limb to the body trunk
- Superficial: toward or at the body surface
- Deep: away from the body surface; more internal
BODY PLANES AND SECTIONS
- A sagittal section divides the body (or organ) into left and right parts.
- A median, or midsagittal , section divides the body (or organ) into equal left and right parts.
- A frontal, or coronal , section divides the body (or organ) into anterior and posterior parts.
- A transverse, or cross , section divides the body (or organ) into superior and inferior part.
(a) Classification based on number of cell layers
Shape of cells o Squamous
- flattened o Cuboidal
- cube-shaped o Columnar
- column-like
(b) Classification based on cell shape
Simple Epithelia
o Single layer of flat cells o Location - usually forms membranes
- Lines body cavities
- Lines lungs and capillaries o Functions in diffusion, filtration, or secretion in membranes
- Simple cuboidal o Single layer of cube-like cells
o Locations
- Common in glands and their ducts
- Forms walls of kidney tubules
- Covers the ovaries o Functions in secretion and absorption; ciliated types propel mucus or reproductive cells
- Simple columnar o Single layer of tall cells o Often includes mucus-producing goblet cells o Location - lines digestive tract o Functions in secretion and absorption ; ciliated types propel mucus or reproductive cells
- Pseudo-stratified columnar
- Single layer, but some cells are shorter than others
- Often looks like a double layer of cells but all cells rest on the basement membrane
- Location - respiratory tract , where it is ciliated
- Functions in absorption or secretion Stratified Epithelia
- Transitional epithelium o Composed of modified stratified squamous epithelium
o Shape of cells depends upon the amount of stretching o Functions in stretching and the ability to return to normal shape o Location - lines organs of the urinary system
Glandular Epithelium
- Gland o One or more cells responsible for secreting a particular product o Secretions contain protein molecules in an aqueous (water-based) fluid
Two major gland types:
- Endocrine gland o Ductless since secretions diffuse into blood vessels o All secretions are hormones
- Exocrine gland o Secretions empty through ducts to the epithelial surface o Include sweat and oil glands Connective Tissue o Found everywhere in the body o Includes the most abundant and widely distributed tissues o Functions
- Binds body tissues together
- Supports the body
- Provides protection
- Bone (osseous tissue) o Composed of
- Bone cells in lacunae (cavities)
- Hard matrix of calcium salts
- Large numbers of collagen fibers o Functions to protect and support the body
- Hyaline cartilage o Most common type of cartilage o Composed of
- Abundant collagen fibers
- Rubbery matrix o Locations
- Larynx
- Entire fetal skeleton prior to birth
- Functions as a more flexible skeletal element than bone
- Blood (vascular tissue) o Blood cells surrounded by fluid matrix called blood plasma
o Fibers are visible during clotting o Functions as the transport vehicle for materials Muscle Tissue o Function is to produce movement o Three types
- Skeletal muscle
- Cardiac muscle
- Smooth muscle Cardiac muscle o Under involuntary control o Found only in the heart o Function is to pump blood o Characteristics of cardiac muscle cells
- Striated
- One nucleus per cell
- Cells are attached to other cardiac muscle cells at intercalated disks Smooth muscle
o Under involuntary muscle o Found in walls of hollow organs such as stomach, uterus, and blood vessels o Characteristics of smooth muscle cells
- No visible striations
- One nucleus per cell
- Spindle-shaped cells
Nervous Tissue
- Composed of neurons and nerve support cells (neuroglia)
- Function is to send impulses to other areas of the body - Irritability – able to respond to stimuli - Conductivity – able to conduct impulses
- Support cells called neuroglia insulate, protect, and support neurons
Tissue Repair (Wound Healing)
- Regeneration o Replacement of destroyed tissue by the same kind of cells
- Fibrosis o Repair by dense (fibrous) connective tissue (scar tissue)
o Whether regeneration or fibrosis occurs depends on:
- Type of tissue damaged
- Severity of the injury
Events in Tissue Repair
- Inflammation o Capillaries become very permeable o Clotting proteins migrate into the area from the blood stream o A clot walls off the injured area
- Granulation tissue forms o Growth of new capillaries o Rebuild collagen fibers
- Regeneration of surface epithelium o Scab detaches
coloring
- Cyanosis - Low oxygen content creates a bluish appearance Dermis
- Dense connective tissue ★ Two layers: ➔ Papillary layer
- Projections called dermal papillae
- Pain receptors
- Capillary loops ➔ Reticular layer
- Blood vessels
- Glands
- Nerve receptors
// FINGERPRINTS //
- Arise from the interaction of an individual’s genes and the developmental environment in the uterus.
- Genes determine general characteristics of patterns that are used for fingerprint classification.
- As the skin on the fingertip differentiates, it expresses these general characteristics.
- This skin is also in contact with the amniotic fluid in the uterus and other parts of the fetus and the uterus, and their position in relation to uterus and the fetal body changes as the fetus moves on its own and in response to positional changes of the mother.
- The area around growing cells on the fingertip is in flux, and is always slightly different from hand to hand and finger to finger.
- Their effect is amplified by the differentiating cells and produces the larger differences that enable the fingerprints of even identical twins to be differentiated.
➔ Skin Structure ● Deep to dermis is the hypodermis
- Not part of the skin
- Anchors skin to underlying organs
- Composed mostly of adipose tissue
//Appendages of the Skin//
● Sebaceous glands
- Produce oil
- Lubricant for skin
- Kills bacteria
- Most with ducts that empty into hair follicles
- Glands are activated at puberty ● Sweat glands
- Widely distributed in skin
- Two types: Eccrine & Apocrine ➔ Eccrine sweat gland
- Open via duct to pore on skin surface
➔ Apocrine sweat gland
- Ducts empty into hair follicles
★ Sweat and Its Function: ➔ Composition :
- Mostly water
- Some metabolic waste
- Fatty acids and proteins (apocrine only) ➔ Function:
- Helps dissipate excess heat
- Excretes waste products
- Acidic nature inhibits bacterial growth - Odor is from associated bacteria ● Hair
- Produced by hair bulb
- Consists of hard keratinized epithelial cells
- Melanocytes provides pigment for hair color
Hair Anatomy Central medulla Cortex surrounds medulla Cuticle on outside of cortex o Most heavily keratinized Associated Hair Structures Hair follicle
o ArrecDermal and epidermal sheath surround hair root o tor pilli o Smooth muscle Sebaceous gland Sweat gland ● Nails
➔ Scale-like modifications of the epidermis - Heavily keratinized ➔ Stratum basale extends beneath the nail bed
- Responsible for growth ➔ Lack of pigment makes them colorless ★ Nail Structures ➔ Free edge ➔ Body ➔ Root of nail
➔ Eponychium – proximal nail fold that projects onto
the nail body the interlocked cuticles, Huxley's and Henle's layers, the outer epithelial root sheath, a deeply stained basement membrane and, finally, the well vascularized connective tissue sheath
Skin Homeostatic Imbalances Infections o Athletes foot Caused by fungal infection o Boils and carbuncles Caused by bacterial infection o Cold sores Caused by virus Infections o Athletes foot Caused by fungal infection o Boils and carbuncles Caused by bacterial infection o Cold sores Caused by virus Burns o Tissue damage and cell death caused by heat, electricity, UV radiation, or chemicals o Associated dangers Dehydration Electrolyte imbalance Circulatory shock Rules of Nines Way to determine the extent of burns Body is divided into 11 areas for quick estimation Each area represents about 9% Severity of Burns
First-degree burns o Only epidermis is damaged o Skin is red and swollen Second degree burns o Epidermis and upper dermis are damaged o Skin is red with blisters Third-degree burns o Destroys entire skin layer o Burn is gray-white or black Critical Burns Burns are considered critical if: o Over 25% of body has second degree burns o Over 10% of the body has third degree burns o There are third degree burns of the face, hands, or feet Skin Cancer Cancer – abnormal cell mass Two types Benign o Does not spread (encapsulated) Malignant o Metastasized (moves) to other parts of the body Skin cancer is the most common type of cancer Types: Basal cell carcinoma o Least malignant o Most common type o Arises from statum basale Squamous cell carcinoma o Arises from stratum spinosum o Metastasizes to lymph nodes o Early removal allows a good chance of cure Malignant melanoma o Most deadly of skin cancers o Cancer of melanocytes o Metastasizes rapidly to lymph and blood vessels o Detection uses ABCD rule
- Composed of small, needlelike pieces of bone called trabeculae and open spaces
- Open spaces are filled by marrow, blood vessels, and nerves Microscopic anatomy of compact bone Osteocytes
- Mature bone cells situated in bone matrix Lacunae
- Cavities in bone matrix that house osteocytes Lamellae
- Concentric circles of lacunae situated around the central (Haversian) canal Central (Haversian) canal
- Opening in the center of an osteon (Haversian system)
- Runs lengthwise through bone
- Carries blood vessels and nerves Osteon (Haversian system)
- A unit of bone containing central canal and matrix rings
- Structural and functional unit of compact bone Canaliculi
- Tiny canals
- Radiate from the central canal to lacunae
- Form a transport system connecting all bone cells to a nutrient supply Perforating (Volkmann’s) canal
- Canal perpendicular to the central canal
- Carries blood vessels and nerves
Bone Fractures Fracture: break in a bone Types of bone fractures Closed (simple) fracture is a break that does not penetrate the skin Open (compound) fracture is a broken bone that penetrates through the skin Bone fractures are treated by reduction and immobilization Closed reduction: bones are manually coaxed into position by physician’s hands Open reduction: bones are secured with pins or wires during surgery Healing time is 6–8 weeks Repair of bone fractures involves four major events
Hematoma (blood-filled swelling, or bruise) is formed Fibrocartilage callus forms
- Cartilage matrix, bony matrix, collagen fibers splint the broken bone Bony callus replaces the fibrocartilage callus
- Osteoblasts and osteoclasts migrate in Bone remodeling occurs in response to mechanical stresses
Axial Skeleton Forms the longitudinal axis of the body Divided into three parts
- Skull
- Vertebral column
- Bony thorax
Skull Two sets of bones form the skull
- Cranium bones enclose the brain
- Facial bones
- Hold eyes in anterior position
- Allow facial muscles to express feelings Bones are joined by sutures Only the mandible is attached by a freely movable joint 8 cranial bones protect the brain Hyoid bone
- Closely related to mandible and temporal bones
- The only bone that does not articulate with another bone
- Serves as a movable base for the tongue
- Aids in swallowing and speech Vertebral Column (Spine) Vertebral column provides axial support
- Extends from skull to the pelvis 26 vertebral bones are separated by intervertebral discs
- 7 cervical vertebrae are in the neck
- 12 thoracic vertebrae are in the chest region
- 5 lumbar vertebrae are associated with the lower back
- Sacrum (formed by fusion of 5 vertebrae)
- Coccyx (formed by fusion of 3– 5 vertebrae) Primary curvatures
- Spinal curvatures of the thoracic and sacral regions
- Present from birth
- Form a C-shaped curvature in newborns Secondary curvatures
- Spinal curvatures of the cervical and lumbar regions
- Develop after birth
- Form an S-shaped curvature in adults Parts of a typical vertebra Body (centrum) Vertebral arch
- Pedicle
- Lamina Vertebral foramen Transverse processes Spinous process Superior and inferior articular proceses
Thoracic Cage Bony thorax, or thoracic cage, protects organs of the thoracic cavity Consists of three parts
- Sternum
- Ribs True ribs (pairs 1–7) False ribs (pairs 8–12) Floating ribs (pairs 11–12)
- Thoracic vertebrae
Appendicular Skeleton Composed of 126 bones
- Limbs (appendages)
- Pectoral girdle
- Pelvic girdle
Bones of the Shoulder Girdle
Also called pectoral girdle Composed of two bones that attach the upper limb to the axial skeletal
- Clavicle
- Scapula Light, poorly reinforced girdle Allows the upper limb a exceptional flexibility
Bones of the Upper Limbs Humerus Forms the arm Single bone Proximal end articulation
- Head articulates with the glenoid cavity of the scapula Distal end articulation
- Trochlea and capitulum articulate with the bones of the forearm The forearm has two bones Ulna—medial bone in anatomical position Proximal end articulation
- Coronoid process and olecranon articulate with the humerus Radius—lateral bone in anatomical position Proximal end articulation
- Head articulates with the capitulum of the humerus Hand Carpals—wrist bones
- 8 bones arranged in two rows of 4 bones in each hand Metacarpals—palm bones
- 5 per hand Phalanges—fingers and thumb
- 14 phalanges in each hand
- In each finger, there are 3 bones
- In the thumb, there are only 2 bones Bones of the Pelvic Girdle Formed by two coxal (ossa coxae) bones Composed of three pairs of fused bones Ilium Ischium Pubis Pelvic girdle = two coxal bones, sacrum Pelvis = two coxal bones, sacrum, coccyx The total weight of the upper body rests on the pelvis Pelvis protects several organs Reproductive organs Urinary bladder Part of the large intestine Bones of the Lower Limbs Femur—thigh bone The heaviest, strongest bone in the body Proximal end articulation
First Semester: ANATOMY & PHYSIOLOGY
Lesson 5: THE MUSCULAR SYSTEM
The Muscular System
organ system consisting of skeletal, smooth,
and cardiac muscles.
It permits movement of the body, maintains
posture, and circulates blood throughout the body.
The muscular
systems in vertebrates are controlled through the nervous system although some muscles can be completely autonomous.
Muscles
a soft tissue found in most animals.
Muscle cells contain protein filaments of
actin and myosin that slide past one another, producing a contraction that changes both the length and the shape of the cell.
Muscles function to produce force and
motion.
Microscopic Anatomy of the Muscle:
Skeletal muscle fibers are long,
multinucleated cells. The membrane of the cell is the sarcolemma; the cytoplasm of the cell is the sarcoplasm. The sarcoplasmic reticulum (SR) is a form of endoplasmic reticulum.
Muscle fibers are composed of myofibrils.
Types of Muscle Tissues:
- Smooth Muscles
is a type of muscle tissue which is used by
various systems to apply pressure to vessels and organs.
Smooth muscle is composed of sheets or
strands of smooth muscle cells.
These cells have fibers of actin and myosin
which run through the cell and are supported by a framework of other proteins.
Smooth muscles are located in the following organs:
Walls of blood Walls of stomach Ureters Intestines In the aorta (tunica media layer) Iris of the eye Prostate Gastrointestinal Tract Respiratory Tract Small arteries Arterioles Reproductive tracts (both genders) Veins Glomeruli of the Kidneys (called mesangial cells) Bladder Uterus Arrector pili of the skin Ciliary muscle Sphincter Trachea Bile duct
- Cardiac Muscles - (also called heart muscle or myocardium) is one of three types of vertebrate muscles , with the other two being skeletal and smooth muscles. It is an involuntary, striated muscle that constitutes the main tissue of the walls of the heart.
- Skeletal Muscles – one of three major muscle types, the others being cardiac muscle and smooth muscle. It is a form of striated muscle tissue, which is under the voluntary control of the somatic nervous system. Most skeletal muscles are attached to bones by bundles of collagen fibers known as tendons.
We have approximately 320 pairs of muscles in the body. They are divided into groups.
// Head Muscles //
The muscles of the head and neck perform
many important tasks, including movement of the head and neck, chewing and swallowing, speech, facial expressions, and movement of the eyes. These diverse tasks require both strong, forceful movements and some of the fastest, finest, and most delicate adjustments in the entire human body.
The muscles of the face are unique among
groups of muscles in the body.
While most muscles connect to and move
only bones, facial muscles mostly connect bones to skin. The muscles of the head are divided into Muscles of Facial Expression, Muscles of Mastication and the Tongue.
I. Muscles of Facial Expression:
- The muscles of facial expression are located in the subcutaneous tissue , originating from bone or fascia, and inserting onto the skin.
- By contracting, the muscles pull on the skin and exert their effects. They are the only group of muscles that insert into the skin. It can broadly be split into three groups:
A. Orbital Group Orbicularis Oculi Corrugator Supercii
B. Nasal Group Nasalis Procerus
C. Oral Group Orbicularis Oris Buccinator Other Oral Muscle
Orbital Group:
Orbicularis Oculi
- is the muscle that surrounds the eye socket and extends into the eyelid It has three distinct parts – palpebral, lacrimal, and orbital.
Palpebral part – gently closes the eyelids. Lacrimal part – involved in the drainage of tears. Orbital part – tightly closes the eyelids.
Corrugator Supercii
It is a much smaller
muscle and is located posteriorly to the orbicularis oculi.
Acts to draw the
eyebrows together, creating vertical wrinkles on the bridge of the nose.
Nasal group:
Nasalis
It is the largest of the
nasal muscles. It is split into two parts: transverse and alar.
The transverse part
compresses the nares, and the alar part opens the nares.
Procerus
The contraction of this
muscle pulls the eyebrows downward to produce transverse wrinkles over the nose.
Depressor Septi Nasi
It pulls the nose
inferiorly, opening the nares.
Oral Group:
Orbicularis Oris
The fibers of the
orbicularis oris enclose the opening to the oral cavity. Purses the lips.
Buccinator
This muscle is located
between the mandible and maxilla, deep to the other muscles of the face. It pulls the cheek inwards against the teeth, preventing accumulation of food in that area.
The Suboccipital Muscle
A group of four
muscles situated underneath the occipital bone.
All the muscles in
this group are innervated by the suboccipital nerve.
1. Rectus Capitis Posterior Major
Extends and rotates the head.
2. Rectus Capitis Posterior Minor
Extends the head
3. Obliquus Capitis Inferior
Extends and rotates of the head
4. Obliquus Capitis Superior
Facilitate the movements of the head
and neck and maintain posture by supporting the atlantoaxial joint.
The Suprahyoid Muscles
A group of four muscles, located superiorly
to the hyoid bone of the neck. They all act to elevate the hyoid bone – an action involved in swallowing.
1. Stylohyoid - Initiates swallowing action 2. Digastric
- Depresses the mandible and elevates the hyoid bone. 3. Mylohyoid - Elevates the hyoid bone and the floor of the mouth. 4. Geniohyoid - Depresses the mandible and elevates the hyoid bone
The Infrahyoid Muscles
are a group of four muscles that are located
inferiorly to the hyoid bone in the neck. They can be divided into two groups:
1. Superficial plane
omohyoid and sternohyoid muscles.
2. Deep plane
sternothyroid and thyrohyoid
muscles.
The Scalene Muscles
They are three
paired muscles located in the lateral aspect of the neck. They act as accessory muscles of respiration , and perform flexion at the neck.
1. Anterior – causes anterior flexion of the neck. 2. Middle – causes lateral flexion of the neck 3. Posterior - elevate the second rib and tilt the neck to the same side. They also act as accessory muscles of inspiration.
// Upper Body Muscles //
Abdominal Muscles, Pectoral Muscles,
Deltoid, Trapezius, Latissimus Dorsi, Erector Spinae, Biceps, Triceps
Abdominal Muscles
They are located between the ribs and the
pelvis on the front of the body. The abdominal muscles support the trunk, allow movement and hold organs in place by regulating internal abdominal pressure.
Pectoral Muscles
(colloquially referred to as "pecs") are the
muscles that connect the front of the human chest with the bones of the upper arm and shoulder. The pectoral region is located on the anterior chest wall. It contains four muscles that exert a force on the upper limb;
- Pectoralis Major - makes up the bulk of the chest muscles and lies under the breast.
- Pectoralis Minor -stabilization, depression, abduction or protraction, internal rotation and downward rotation of the scapula. It elevates the ribs for deep inspiration when the pectoral girdle is fixed or elevated.
Deltoid
It is a rounded, triangular muscle located on
the uppermost part of the arm and the top of the shoulder.
It is named after the Greek letter delta,
which is shaped like an equilateral triangle.
1. Anterior - abduction, flexion, and internal rotation 2. Lateral - involved in shoulder abduction when the shoulder is internally rotated. It is involved in shoulder flexion when the shoulder is internally rotated. 3. Posterior - act with the latissimus dorsi to produce extension of the arm during ambulation.
Trapezius
It moves the scapula and supports the arm.
Biceps
A large muscle in the upper arm which turns
the hand to face palm uppermost and flexes the arm and forearm.
It is a powerful prime mover for flexion of the
forearm and acts to supinate the forearm
Triceps
A large muscle on the back of the upper
limb of many vertebrates. Responsible for extension of the elbow joint (straightening of the arm).
// Lower Body Muscles //
Gluteus
Any of three muscles in each buttock which
move the thigh, the largest of which is the gluteus maximus.
- Gluteus Maximus - movement of the hip and thigh
- Gluteus Medius - stabilizes the pelvis while standing or walking.
- Gluteus Minimus - hip stabilization and abduction.
Quadriceps
A large muscle group that includes the four
prevailing muscles on the front of the thigh. It is the great extensor muscle of the knee, forming a large fleshy mass which covers the front and sides of the femur.
1. Vastus Lateralis - extend the lower leg and allow the body to rise up from a squatting position. 2. Vastus Intermedius - primary function is knee extension 3. Vastus Medialis - extend the leg at the knee and to stabilize the patella, which is also known as the kneecap. 4. Rectus Femoris - By acting on the hip joint, it helps with thigh flexion. When its patellar
attachment is fixed, this muscle aids to flex the pelvis anteriorly towards the thigh.
Hamstrings
It allows the thigh to extend, tibia to rotate,
and knee to flex. Susceptible to injury.
Gastrocnemius
It is a superficial two-headed muscle that is
in the back part of the lower leg of humans Soleus
The plantar flexor muscle of the ankle. It is
capable of exerting powerful forces onto the ankle joint.
// Hand Muscles //
Intrinsic hand muscles
Thenar Muscles – in the thumb
- dexterity of the thumb: buttoning a collar or shaking a hand
- Innervation: by median nerve
- Recurrent median nerve branch innervates the muscles after traversing the carpal tunnel **_1. Abductor Pollicis Brevis Muscle
- Flexor Pollicis Brevis Muscle
- Opponens Pollicis Brevis Muscle_**
Hypothenar – in the pinkie
- Traverses tunnel formed by connective tissue attaching to the pisiform bone called Gianni’s Canal, after transverse enters to hand and gives innervation to hypothenar muscles as well as other muscles in the hand. **_1. Abductor Digiti Minimi Muscle
- Flexor Digiti Minimi Muscle
- Opponens Digiti Minimi Muscle_**
Lumbrical – arise from flexor digitorum profundus tendons and then course up so they arise on front of hand called the Palmar Surface or Volar Surface and tendons course to back of the digits.
Origin:
**_1. Metacarpal
- Proximal (Phalange)
- Middle
- Distal_** Metacarpal Phalangeal joint (MCP) – between metacarpal and phalange. Proximal Interphalangeal joints (PIP) – between proximal and middle. Distal Interphalangeal joints (DIP) – between middle and distal.
- Originates on the bone of fifth metatarsal an inserts onto the base of proximal phlanx.
- Function: flex little toe Planter Interossei Muscle
- Originates medially on the metatarsals 3-4-
- Insert onto the base digits 3-
- Function: adduct the toes 3-5 at the MTP joints Dorsal Interossei Muscle
- Originates on both sides of the metatarsal two three and four.
- First 3 muscles insert laterally to the bone of proximal phalanges two to four
- The fourth muscles inserts in middle only
- Function: Adduct the metatarsal phalangeal joint
Dorsal Group Extensor Digitorum brevis
- Originates both superiorly and laterally on the calcaneus
- Function: extend digits at the MTP joints
First muscles inserts on the proximal base of the greater toe phalanx
While others inserts laterally to the accentuate digitorum longus tendon
// Muscle Movements //
The 5 Golden Rules of Skeletal Muscle Activity:
- With a few exceptions, all skeletal muscles cross at least one joint.
- Typically, the bulk of a skeletal muscle lies proximal to the joint crossed.
- Skeletal muscles have at least 2 attachments, the origin, and the insertion.
- Skeletal muscles can only pull; they never push.
- During contraction, a skeletal muscle insertion moves toward the origin.
- Origin and Insertion
- Every one of our 600-odd skeletal muscles is attached to aa bone, or to other connective tissue structures, at no fewer than 2 points. One of these points, the Origin, is attached to the immovable or less movable bone. Think of the origin as the anchor or leverage point.
- Another point, the Insertion, is attached to the movable bone. When the muscle contracts, the insertion moves towards the origin.
- Generally, body movement occurs when muscles contract across joints. The type of movement depends on the mobility of the joint and the location of the joint in relation to the joint. The most obvious example of the action of muscles on bones is the movements that occur at the joints of the limbs.
// Common Types of Body Movements //
1. Flexion – is a movement that decreases the angle of the joint and brings two bones closer together. 2. Extension – opposite of flexion. It is a movement that increases the angle between two bones or parts of the body. 3. Rotation – movement of a bone around its longitudinal axis. 4. Abduction – moving of a limb away from the midline of the body. 5. Adduction – movement of a limb toward the midline of the body. 6. Circumduction – combination of flexion, extension, abduction, and adduction.
// Special Movements //
1. Dorsiflexion and Plantar Flexion – Up and down movements of the foot at the ankle. 2. Inversion and Eversion – inverting the foot is turning the sole medially and everting the foot means turning the sole laterally. 3. Supination and Pronation – Supination is when the palm faces upward and Pronation is when the palm faces downward. 4. Opposition – this is when you move your thumb to touch the tips of the other fingers.
First Semester: ANATOMY & PHYSIOLOGY
LESSON 6: THE NERVOUS SYSTEM
The Nervous system is a complex network of nerves and cells that carry messages to and from the brain and spinal cord to various parts of the body. The central nervous system consists of the brain and spinal cord. The brain plays a central role in the control of most bodily functions, including awareness, movements, sensations, thoughts, speech, and memory. Some reflex movements can occur via spinal cord pathways without the participation of brain structures.
The brain is an organ that serves as the center of the nervous system in all vertebrates and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as vision. It is the most complex organ in a vertebrate's body.
The brain has 6 important parts : A. Cerebrum or the cerebral hemispheres are the most superior part of the brain. The Cerebral cortex or the outermost layer of the brain is divided into 4 regions or lobes:
1. Frontal Lobe - is the part of the brain that controls important cognitive skills in humans, such as emotional expression, problem-solving, memory, language, judgment, and sexual behaviors. It is, in essence, the “control panel” of our personality and our ability to communicate. 2. Parietal Lobe - The parietal lobes are divided into two functional regions. One involves sensation and perception and the other is concerned with integrating sensory input , primarily with the visual system. The first function integrates sensory information to form a single perception (cognition). 3. Occipital lobe - is the visual processing area of the brain. It is associated with visuospatial processing , distance and depth perception, color determination, object and face recognition, and memory. 4. Temporal lobe - is involved in primary auditory perception, such as hearing, and holds the primary auditory cortex. The primary auditory cortex receives sensory information from the ears and secondary areas process the information into meaningful units such as speech and words.
B. Cerebellum - is a major structure of the hindbrain that is located near the brainstem. This part of the brain is responsible for coordinating voluntary movements. It is also responsible for a number of functions including motor skills such as balance, coordination, and posture. C. Diencephalon- is a division of the forebrain (embryonic prosencephalon), and is situated between the telencephalon and the midbrain (embryonic mesencephalon). It consists of structures
that are on either side of the third ventricle, including the thalamus, the hypothalamus, the epithalamus, and the subthalamus. D. Midbrain - The midbrain or mesencephalon is the forward-most portion of the brainstem and is associated with vision, hearing, motor control, sleep and wakefulness, arousal (alertness), and temperature regulation. E. Pons - The pons is a portion of the brain stem, located above the medulla oblongata and below the midbrain. It is a bridge between various parts of the nervous system, including the cerebellum and cerebrum, which are both parts of the brain F. Medulla Oblongata - the continuation of the spinal cord within the skull, forming the lowest part of the brainstem and containing control centers for the heart and lungs.
Protection of Central Nervous System Nervous Tissues are soft and delicate, even slight pressure can injure the irreplaceable neurons. Nature tries to protect the brain and spinal cord by enclosing them within the bone (the skull and the vertebral column). There is also 3 additional protection for the CNS: A. Meninges There are 3 connective tissue membranes covering the CNS:
1. Dura Mater - the outermost layer, leathery, and double-layered 2. Arachnoid Mater - middle, meningeal layer
- Pia Mater - outermost layer, clings tightly to the surface of the brain. B. Cerebrospinal Fluid (CSF )-is a watery “broth” with components similar to blood plasma. It is a clear, colorless body fluid found in the brain and spinal It is produced by specialized ependymal cells in the choroid plexuses of the ventricles of the brain and absorbed in the arachnoid granulations. C. Blood-brain Barrier- (BBB) is a highly selective semipermeable border of endothelial cells that prevents solutes in the circulating blood from non-selectively crossing into the extracellular fluid of the central nervous system where neurons reside.
The Spinal Cord
The spinal cord is a long, thin, tubular structure made up of nervous tissue, which extends from the medulla oblongata in the brainstem to the lumbar region of the vertebral column. It encloses the central canal of the spinal cord , which contains cerebrospinal fluid. There are 31 pairs of nerves in the Spinal Cord; 8 cervical, 12 thoracics, 5 lumbar, 5 sacral, and 1 coccygeal. Each pair connects the spinal cord with a specific region of the body.
