Anatomy and Physiology Fundamentals

Anatomy and Physiology

• Anatomy studies the structure of the body.
• Physiology studies the processes and functions of the body.

Levels of Organization

• Atoms combine to form molecules.
• Molecules form organelles, which are the functional components of cells.
• Cells are the basic structural and functional units of an organism.
• Tissues are groups of similar cells performing specific functions.
• Organs consist of different tissues working together.
• Organ systems are groups of organs that cooperate to accomplish common purposes.
• Organ systems combined make up the organism

Homeostasis

• Homeostasis refers to the maintenance of a stable internal environment despite external or internal fluctuations.
• Set point is the normal or average value of a variable.
• Normal range represents the extent of increase or decrease around a set point.

Negative Feedback

• Negative feedback is the primary mechanism for homeostatic regulation.
• Negative feedback works to decrease or reverse any deviation from the set point.
• Receptor detects changes in variables and stimuli.
• The control center (often the brain) then receives the receptor signal, establishes the set point and sends signals to the effector.
• The effector is directed by the control center to adjust a variable back to the set point.

Positive Feedback

• Positive feedback amplifies the initial stimulus.
• Enhances the deviation from the set point outside of the normal range.

Anatomical Position

• Anatomical position is standing erect with feet forward and palms facing forward.

Directional Terms

• Inferior means below.
• Superior means above.
• Anterior means toward the front of the body.
• Posterior means toward the back of the body.
• Dorsal is synonymous with posterior.
• Ventral is synonymous with anterior.
• Proximal means closer to a point of attachment.
• Distal means further from a point of attachment.
• Lateral means away from the midline of the body.
• Medial means toward the midline of the body.
• Superficial means toward or on the surface.
• Deep means away from the surface, internal.
• Supine means laying face up.
• Prone means laying face down.

Abdominal Regions

• The nine regions of the abdomen are: Right Hypochondriac, Epigastric, Left Hypochondriac, Right Lumbar, Umbilical, Left Lumbar, Right Iliac, Hypogastric, and Left Iliac.

Body Planes

• Sagittal plane separates the body into right and left parts.
• Median plane is a sagittal plane along the midline dividing the body into superior and inferior parts.
• Transverse plane is a horizontal plane.

Body Cavities

• Dorsal cavity encloses the organs of the nervous system.
• Ventral cavity contains the majority of internal organs, known as viscera.
• The ventral cavity includes the thoracic and abdominopelvic cavities.
• The thoracic cavity is within the chest wall and diaphragm including the pleural cavity and the mediastinum.
• The abdominopelvic cavity is enclosed by the abdominal muscles including the abdominal cavity and pelvic cavity.
• Serous membranes are double-layered membranes lining trunk cavities and covering organs in the ventral body cavity.

Serous Membranes

• Pericardium surrounds the heart within the pericardial cavity.
• Pleura surrounds the lungs within the pleural cavity.
• Peritoneum surrounds the abdominopelvic cavity and its organs within the peritoneal cavity.

Tissues and Histology

• Tissue is a group of similar cells with a common structure and function, along with the surrounding extracellular substance.
• Histology is the study of tissue.

Tissue Types

• Epithelial tissue is a covering or lining tissue.
• Connective tissue is a diverse primary tissue type that makes up part of every organ in the body.
• Muscle tissue contracts for movement.
• Nervous tissue coordinates and controls body activities.

Epithelial Tissue

• Epithelium covers and protects surfaces, both outside and inside the body.
• Exocrine glands secrete substances like saliva, sweat, digestive secretions, and sebaceous (oil).
• Endocrine glands produce hormones and release them into the bloodstream.
• Cilia are structures that move materials over the top of the cell.
• Microvilli increase surface areas.

Epithelial Tissues Types

• Simple squamous epithelium is a single layer of thin, flat cells that functions in diffusion, filtration, and secretion.
• Simple cuboidal epithelium is a single layer of cube-like cells that is involved in active transport, facilitated diffusion, or secretion and absorption.
• Simple columnar epithelium is a single layer of tall, thin cells specialized for secretion and absorption.
• Pseudostratified columnar epithelium is a single layer of short and tall cells that secretes mucus to cover its free surface and move mucus.
• Stratified squamous epithelium consists of many layers of cells and provides protection and acts as a barrier.
• Transitional epithelium has many layers of cells that are not stretched and cuboidal, stretched they are squamous to allow for stretching and protection.

Connecting Epithelial Cells

• Desmosomes provides mechanical links that bind cells together.
• Hemidesmosomes are half desmosomes that anchor cells to the basement membrane.
• Tight junctions form barriers and help cells anchor together that prevent the passage of materials
• Gap junctions are small channels that allow small molecules and ions to pass from one epithelial cell to an adjacent one, to coordinate the activities of the cells.

Connective Tissue

• Loose connective tissue includes areolar, adipose, and reticular tissues.
• Dense connective tissue can be regular/irregular collagenous or regular/irregular elastic.
• Connective tissue gives structure to other tissues and organs in the body along with support and protection.

Extracellular Matrix

• The extracellular matrix (ECM) of connective tissue has three major components: protein, fibers, ground substance, and fluid.
• Collagen fibers are flexible and resist stretching.
• Reticular fibers form a supporting network.
• Elastic fibers have the ability to return to their original shape.
• Ground substance consists of non-fibrous protein and other shapeless molecules.

Suffixes

• "-blasts" create matrix.
• "-cytes" maintain matrix.
• "-clasts" breakdown matrix.

Connective Tissue Types

• There are two types of connective tissue - embryonic and adult.
• Adult connective tissue is further divided into connective tissue proper, supporting connective tissue, and fluid connective tissue.
• Connective Tissue Proper includes Loose and Dense.
• Supporting Connective Tissue includes Hyaline cartilage.
• Fluid Connective Tissue includes Blood.

Muscle Tissue

• Skeletal muscle attaches to bones and enables movement and it is striated and is voluntary controlled.
• Cardiac muscle is in the heart for pumping blood, is striated and involuntary.
• Smooth muscle is in hollow organs, the skin, and the eyes to assist with various functions, and is not striated, and is involuntary.

Nervous Tissue

• Neurons conduct electrical signals and are composed of a cell body, dendrites, and an axon.
• Glial cells nourish, protect, and insulate neurons.

Tissue Membranes

• Tissue membranes are thin sheets or layers of tissue that cover a structure or lines of cavity.
• Cutaneous membranes are an external body surface.
• Mucous membranes line cavities that open to the outside of the body and perform protection, absorption, and secretion.

Integumentary System Composition

• The main components of the integumentary system are the skin and accessory structures.

Integumentary System Function

• Protection is provided from abrasion and ultraviolet light.
• Sensation by sensory receptors for detecting heat, cold, touch, pressure, and pain.
• Vitamin D production when exposed to ultraviolet light.
• Temperature regulation by the amount of flow beneath the skin surface and the activity of sweat glands.
• Excretion of waste products through the skin and in gland secretions.

Skin Layers

• The epidermis is the most superficial (top) layer of skin and provides protect protection.
• The dermis provides structural strength.
• The subcutaneous tissue connects skin to underlying muscle or bone and that is not part of the skin.

Epidermis

• The epidermis function is to prevent water loss and resists abrasion.
• Cells in epidermis perform mitosis, as new cells are made pushing the top cells to eventually slough off (flake off).
• Strata Layers include Basale, spinosum, granulosum, lucidum, and corner.
• Cells are filled with protein keratin that makes them rigid and durable and they undergo keratinization.
• The top layer, dead squamous cells filled with keratin prevents water loss.
• Thick skin has all 5 strata and is located in areas of pressure or friction.
• Thin skin has 4 layers of strata - lacks stratum lucid and covers rest of the body.

Dermis

• Dermis is dense collagenous connective tissue that provides structual support.
• Cleavage lines show tension that is more resistant to stretch.
• Dermal papillae are projections found in the upper part towards the epidermis.

Hypodermis/Subcutaneous Tissue

• Skin rests on loose connective tissue, which includes adipose tissue and connects the bone to muscle.

Accessory Structures in Skin

• Accessory structures include hair, glands, and nails.
• The function of structures is for protection, thermoregulation, and for sensory roles.

Hair

• Hair follicle is an invagination of the epidermis.
• The hair bulb at the base of the hair root.
• Hair root is below the surface.
• Hair shaft protrudes above the surface of the skin.

Glands

• Apocrine sweat glands produce a thick secretion rich in organic substances and becomes more active at puberty in armpits and genitalia.
• Arrector pili muscle is attached to smooth muscle cells.
• Sebaceous glands produce sebum an oily substance.
• Eccrine sweat glands located in almost every part of the skin, but most numerous in the palms and souls produce sweat for thermal regulation.

Nails

• Nails are thin plates consisting of layers of dead cells that contain a very hard keratin.
• Nail matrix, are epithelial cells, gives cells creating nail.

Thermoregulation

• Blood vessels in the dermis dilate to enable more blood flow casing heat to dissipate.
• Sweat assists during evaporative cooling for loss of heat.
• Heat is conserved, if begins to drop below normal, by the construction of thermal blood vessels reducing blood flow to the skin.

Skeletal System

• The skeletal system functions for body support, organ, movement, mineral storage (calcium/phosphorus), and blood cell production.
• Bone is connective tissue in a large ECM containing of protein fibers of collagen and a ground substance of mineralized proteoglycans.
• Hydroxyapatite is primarily a calcium phosphate crystal.

Bone Cells

• Osteoblasts (bone-building) are responsible for the formation of bone growth, and the repair and remodeling of it by producing collagen and proteoglycans.
• Osteocytes bone maintain matrix and are long lived.
• Osteoclasts (bone-destroying) contribute to bone repair and remodeling existing bone, called bone reabsorption.

Ossification

• Ossification is The formation of a new bone by osteoblasts.

Bone Structures

• Spongy bone contains interconnecting rods or plates of bone called trabeculae, less bone matrix, and more space.
• Compact bone is denser, contains more matrix, and has fewer pores than spongy bone.
• The function unit of compact bone is an osteon.
• Lamellae are concentric rings of bone matrix which surround the central canal.

Long Bone Anatomy

• The diaphysis composed of compact bone around a hollow center is the center.
• Epiphysis are the ends.
• Articular cartilage covers the ends.
• The epiphyseal plate is located between the epiphysis and the diaphysis.

Bone Marrow

• Red marrow: blood forming cells location.
• Yellow marrow: is mostly fat (adipose tissue).

Bone Membranes

• Periosteum: the outer surface that is covered by connective tissue membrane.
• Endosteum: single cell layer of connective tissue that lines the internal within the bone.

Endochondral Ossification

• Endochondral ossification is bone formation within a cartilage model that is replaced by bone with a primary forming bones in the diaphysis and then secondary forms bone in the epiphysis.
• Bone remodeling occurs.
• The epiphyseal plate is location for bone growth.

Bone Homeostasis

• Calcium is a critical nutrient in the body (Muscle contraction).
• Bone has a lot of calcium stored in it and regulates blood calcium level levels.
• Osteoclast activity levels increase with low blood calcium.
• Osteoclast activity levels decrease with high blood calcium.
• Calcium in bone is regulated by the hormones including parathyroid, calcitriol, and calcitonin.
• Parathyroid is secreted for osteoblast creation to increase blood calcium.
• Calcitriol works with the secretion to increase osteoclast activity for the release of calcium.
• Calcitonin is secreted to decrease osteoclast activity.

Bone Structure

• Axial axis is in center axis containing the skull, the vertebral column, and the thoracic cage.
• Appendicular is a skeleton consisting of limbs and girdles, zones upper and lower limbs attach.
• Long is bones longer than wide and wide (ex:limbs)
• Short can be approximated at they are long. (ex:wrist, ankle)
• Flat contains thin and flattened shaped (ex:sternum)
• Irregular Bones includes vertebrae and facial bones.

Articulation (Joints)

• Articulation is when two bones come together.

Fibrous

• A fibrous joint is connected by fibrous connective tissue with little to now movement (ex:skull, tooth,socket)

Cartilaginous

• A cartilaginous is created through cartilage that has little to no movement (ex:intervertebral disk)

Synovial

• Synovial joint has joints that is connected with liquid in order to connect most appendicular skeleton joints.

Synovial Structure

• Surrounding liquid filled capsule that houses two layers of Fibrous capsule and membrane.

Types Of Movement

• Flexion and Extension of joints through elbow and knee.
• Pronation is when movement is faced towards palms down.
• Supination occurs when faced facing palms up
• Rotation is moving body parts/
• Abduction is the a point moving body parts away.
• Adduction is the opposite as something moves in midline.
• Circumduction is moving freely with shoulder joining.

Vertebral Column

• Column consists of Cervical Atlas with an Axis consisting of vertbreal curves, a Thoracic cage that covers 12 ribs.

The Muscular System

• Three types exist Skeletal Muscle, Smooth, and Cardiac that have intercalated disks to connect the joints together. Skeletal is Attatchched to conscious moment through striated connection Cardiac is involved with the hearts involunterary striated flow Smooth is involved in location and involutnarity

System Function

• System involved in the bodys movement with posture, respiration, production, communication, contruction, heart.

Cell Membranes

• Electrical components consist of Sarcolemma, T Tubule, Sarcoplasm

Mechanical Components

• Mechanical consistis of Myofibril with two componenets of thin and thick layers, containing action, actin, and mysoin.

Neuromuscular Junction

• Nuromuscular junction is the connection towards muscle fiber.

Fiber Model

• Fiber model is based on shorting of sarcomone depending upon atp action.

Mastication

• Mastication is the involvedment of closing of jaw for temporalis.