Physio Part 1

Epithelial Tissue

Thin continuous protective layer of cells, can line outer surface and inner surfaces of organs, blood vessels, etc..

Simple Squamous

Type of epithelial tissue consisting of a single layer of flat cells, allows passage of materials through diffusion or filtration

Stratifies Squamous

Strongest type of epithelial tissue composed of multiple layers of flat flexible cells, providing protection against abrasion and penetration,

Glandular Epithelial Cells

specialized epithelial cells that produce and secrete substances such as hormones, enzymes, and mucus.

Merocrine Secretion

a type of exocrine secretion where cells secrete substances via exocytosis without losing cellular material, commonly seen in sweat and salivary glands, active transport secretes the molecules through the membrane.

Apocrine Secretion

a type of exocrine secretion where a portion of the cell's cytoplasm is released along with the secreted substances, often seen in sweat glands and mammary glands. Top portion of cell is pinched off

Holocrine Secretion

is a type of exocrine secretion where the entire cell disintegrates to release its contents, commonly found in sebaceous glands.

Stratum corneum

First layer of skin, layer of dead flattened cells

Stratum Granulosum

Second Layer of Skin, spindle shaped cells that are involved in the process of keratinization, where cells produce keratin and begin to lose their nuclei.

Stratum Spinosumm

Third layer of skin, spiny appearance because of desmosomes connecting adjacent cells.

Stratum Basale

4th Layer of Skin, mitotically Active cuboidal cells that divide to produce new skin cells

Fifth layer of skin

Dermis layer under the epidermis

Skeletal Muscle Tissue

Multi nucleated, striated pattern, with voluntary control, attached to skeleton through tendons.

Cardiac Muscle Tissue

Single Nucleus, striated patter, and involuntary control

Smooth Muscle Tissue

Single nucleus, non striated, and involuntary control.

Functions of Muscle Tissue

Movement, blood circulation, generation of heat, support, and protection

Step 1 of muscle contraction

Action Potential from central nervous system initiates muscle contraction, can be voluntary or involuntary

Step 2 of Muscle Contraction

Action potential travels down motor neuron to neuromuscular junction, depolarization of the motor neuron terminal causes voltage gated calcium channels to open, allowing Ca to enter neuron.

Step 3 of Muscle Contraction

Calcium influx into neuron triggers realze of ACh, ACh is then relased by exocytosis into synaptic cleft between neuron and muscle fiber.

Step 4 of Muscle Contraction

ACh binds to receptors on the sarcolemma of muscle fiber, ACh binds to ACh receptors, opening ligand gated Na channels, sodium increase depolarizes muscle cell membrane. generating a muscle action potential.

Step 5 of Muscle Contraction

The muscle action potential spreads along the sarcolemma and down the t-tubules

Step 6 of Muscle Contraction

Depolarization of t-tubules activates voltage sensitive proteins that trigger calcium release from sarcoplasmic reticulum (SR), the SR release Ca into the sarcoplasm through calcium release channels.

Step 7 of Muscle Contraction

Calcium Binds to troponin C on thin actin filaments

Step 8 of Muscle Contraction

Troponin undergoes a conformational change that moves tropomyosin. This exposes the myosin binding sites on actin, without calcium bound to troponin, tropomyosin blocks these bindings sites, preventing contraction.

Step 9 of Muscle Contraction

Myosin head in energized state bind to actin, forming cross bridges, the myosin heads contain ADP and inorganic phosphate, and is in the ready position

Step 10 of Muscle Contraction

Release of inorganic phosphate and ADP produces the power stroke, myosin head pivots, pulling actin filament toward the center of the sarcomere and brining the z lines closer.

Step 11 of Muscle Contraction

New ATP molecule binds to myosin, allowing it to release the actin filament

Step 12 of Muscle Contraction

ATP is hydrolyzed, re-readying the myosin head for another power stroke or returning it to a ready state for another contraction cycle.

Step 13 of Muscle Contraction

Relaxation occurs when calcium is actively pimped back into the SR, as CA levels in the sarcoplasm decrease, calcium dissociates from troponin, tropomyosin again block myosin binding sites and muscle contraction is turned off.

Crossed Extensor Reflex

A spinal reflex that helps maintain balance by causing the opposite limb to extend when one limb is withdrawn from a painful stimulus.

elastic connective tissue

A type of connective tissue that provides support and flexibility, containing a high proportion of elastin fibers. It allows structures like blood vessels and lungs to stretch and recoil.

Collagenous connective tissue

A type of connective tissue that provides strength and support, primarily made up of collagen fibers. It is found in tendons, ligaments, and the dermis of the skin. Produced by cells called fibroblasts

Areolar Connective Tissues

a widely distributed, soft, and flexible type of loose connective tissue that provides essential cushioning and support throughout the body

Reticular Connective Tissue

A type of connective tissue that forms a supportive framework for organs, composed of a network of reticular fibers and cells. It is also produced from fibroblasts

Adipose Connective Tissue

A type of loose connective tissue that stores fat, providing insulation and cushioning for the body, while also serving as an energy reserve.

Hyaline Cartilage

A type of cartilage that is glassy and smooth, providing support and flexibility in joints, respiratory tracts, and the embryonic skeleton. Allows for bones to glide over one another. Needed for the formation of bones

Elastic Cartilage

A type of cartilage characterized by a dense network of elastic fibers, providing strength and flexibility.

Fibrocartilage

A type of cartilage that contains a high density of collagen fibers, offering tensile strength and the ability to withstand heavy pressure. It is commonly found in intervertebral discs, pubic symphysis, and menisci, shock absorber

Compact Bone

Cortical bone, dense and forms the outer layer of bones, providing strength and support. Contains tightly packed structural units called osteons, which facilitate the transport of nutrients and waste.

Spongy Bone

Cancellous or trabecular bone, lighter and less dense than compact bone. It contains trabeculae, which are small, needle-like structures that create a network for housing bone marrow and blood vessels.

Long Bones

Characterized by their elongated shape and consist of a shaft, called the diaphysis, along with two ends, known as epiphyses. They are primarily composed of compact bone and are crucial for movement, structure, and support in the body (Femur, humerus, and tibia)

Short Bones

Bones that are roughly cube-shaped and provide stability and support with little movement. They typically consist of spongy bone covered by a thin layer of compact bone (Carpals and Tarsals)

Flat Bones

Bones that are thin and flat in shape, providing protection to internal organs and serving as attachment points for muscles. (Ribs and pelvis)

Sesamoid Bones

Bones embedded within tendons that help to reduce friction and modify pressure, often found in locations like the kneecap.

Pneumatic Bones

Bones that contain air spaces, which reduce weight and may assist in voice resonance, commonly found in the skull.

Irregular Bones

Bones that have complex shapes, providing support and protection while allowing for various attachment points for muscles. Examples include the vertebrae and facial bones.

Epiphysis

The end part of a long bone, initially separated from the main bone by a growth plate and involved in joint formation.

Epiphyseal Cartilage

The cartilage located at the growth plate of long bones, allowing for bone lengthening during growth and contributing to joint function.

Metaphysis

The region of a long bone between the epiphysis and the diaphysis, where growth occurs during development and where the epiphyseal plate is located.

Diaphysis

The main shaft of a long bone, providing structural support and containing the medullary cavity, which houses bone marrow.

Osteocystes

mature bone cells that maintain bone tissue by regulating the metabolism of calcium and phosphate.

Osteoblasts

Bone cells responsible for forming new bone by secreting the bone matrix and aiding in mineralization.

Osteoclasts

large bone cells that break down bone tissue and are involved in bone remodeling by resorbing bone mineral and matrix.

Osteonal System

The structural unit of compact bone, consisting of osteons, which are cylindrical structures containing a central canal, surrounded by concentric layers of bone matrix and osteocytes.

Periosteum

A dense layer of vascular connective tissue enveloping the bones except at the surfaces of the joints. It serves as an attachment point for muscles and contains nerves and blood vessels.

Canaliculi

small channels in bone that connect osteocytes and facilitate communication and nutrient exchange between them.

Intramembranous Ossification

The process of bone development where bone forms directly within a connective tissue membrane, primarily in flat bones like the skull and clavicle.

Endochondral Ossification

The process of bone development where cartilage is replaced by bone tissue, typically occurring in long bones and most of the skeleton.