Muscular & Integument Systems Review

Flashcards covering key vocabulary terms and definitions from the lecture on Muscular and Integumentary Systems.

Epithelial tissue

One of the four basic tissue types of the body.

Nervous tissue

One of the four basic tissue types of the body.

Connective tissue

One of the four basic tissue types of the body.

Muscle tissue

One of the four basic tissue types of the body, categorized into skeletal, cardiac, and smooth muscle.

Muscles

Main contractile tissues of the body involved in movement, causing motion, producing force, maintaining posture, and generating heat.

Muscle fiber

An individual muscle cell that receives nerve impulses, converting chemical energy into mechanical energy for muscle contraction.

Voluntary muscles

Muscles that can be controlled consciously by thought, such as skeletal muscles.

Involuntary muscles

Muscles automatically controlled by the nervous system and cannot be moved at will, such as smooth and cardiac muscles.

Smooth muscle

Found in places like the eyes, air passageways, stomach, intestines, urinary bladder, blood vessels, and reproductive tract; carries out unconscious, internal movements; nonstriated and involuntary.

Skeletal muscle

Controlled by the conscious mind, moves the bones of the skeleton; commonly thought of as 'muscles'; striated and voluntary.

Cardiac muscle

Found only in the heart, making up most of its structure; contracts continuously without rest; striated and involuntary.

Striated muscle

Muscle cells that have a striped appearance under a microscope due to alternating dark and light bands, characteristic of skeletal and cardiac muscle.

Intercalated discs

Specialized junctions that securely fasten cardiac muscle cells together and transmit impulses from cell to cell, allowing coordinated contraction.

Visceral smooth muscle

Found in the walls of many internal soft organs (e.g., stomach, intestine), forming large sheets and performing large, rhythmic peristaltic contractions.

Multi-unit smooth muscle

Small and delicate smooth muscle cells or groups found where precise, delicate contractions are needed (e.g., iris, small blood vessels); require autonomic nerves to contract.

Fascia

Dense regular connective tissue that lies over muscles, supporting, separating, and connecting them to other structures.

Adipose Tissue (Fat)

Connective tissue that cushions organs, provides insulation, and stores vitamins.

Tendons

Tough, fibrous connective tissue bands that attach most skeletal muscles to bones.

Aponeuroses

Broad sheets of fibrous connective tissue that attach some muscles to bones or other muscles.

Linea alba (white line)

The most prominent aponeurosis, a band of fibrous connective tissue that runs along the ventral midline, serving as an attachment site for abdominal muscles.

Ligaments

Bands of fibrous connective tissue present in and around many synovial joints, connecting the bones of joints to each other.

Insertion of Muscle

The site of a muscle attachment that undergoes most of the movement when the muscle contracts.

Origin of Muscle

The more stable site of a muscle attachment that moves less when the muscle contracts.

Agonist (prime mover)

A muscle or muscle group that directly produces a desired movement.

Antagonist

A muscle or muscle group that directly opposes the action of an agonist, helping to smooth out movements.

Synergist

A skeletal muscle that contracts at the same time as an agonist and assists it in carrying out its action.

Fixator

Muscles that stabilize joints to allow other movements to take place.

Rectus

A term in muscle naming that means 'straight', indicating the direction of muscle fibers (e.g., rectus abdominis).

Extensor muscles

Muscles that straighten limbs.

Flexor muscles

Muscles that bend joints.

Abductor muscles

Muscles that move limbs away from the midline of the body.

Adductor muscles

Muscles that move limbs toward the midline of the body.

Integumentary System

A body system that includes the skin, hair, glands, claws/nails, hooves, and horns.

Integument

One of the largest and most extensive organs in the body, composed of all four tissue types, covering and protecting underlying structures, and forming a critical barrier.

Primary functions of Integumentary System

Protection against disease, physical damage, dehydration, overheating, freezing; houses sensory receptors; regulates body temperature; produces Vitamin D; secretes/excretes substances.

Epidermis

The relatively thin, tough, outermost keratinized and avascular layer of the skin.

Dermis (Corium)

The middle layer of the integument, making up its greatest portion and responsible for most of the structural strength of the skin; highly fibrous.

Hypodermis (Subcutaneous layer)

The thickest and deepest layer of skin, residing below the dermis, allowing skin to move freely over underlying structures, composed of areolar tissue.

Keratinocytes

Epidermal cells that produce keratin, a tough, fibrous, waterproof protein.

Keratin

A tough, fibrous, waterproof protein that makes up structures like scales, beaks, claws, feathers, and is a major component of the epidermis, nails, hair, horns, and hooves.

Keratinization

The normal formation of keratin inside epithelial cells of the skin, where cells fill with keratin granules as they mature.

Melanocyte

A cell in the epidermis that produces melanin pigment.

Langerhans cell

A macrophage that originates in bone but migrates to the skin, where it phagocytizes microinvaders and stimulates the immune system.

Merkel cell

A cell associated with sensory nerve endings at the epidermal-dermal junction, thought to aid in the sensation of touch.

Stratum corneum

The outermost, horny layer of the epidermis, which is relatively waterproof and prevents foreign substances from entering the body.

Melanin

A pigment produced by melanocytes, a main contributor to skin color, and primarily functions to filter out ultraviolet radiation from sunlight.

Stratum lucidum

The clear layer of the epidermis, present in thick skin.

Stratum granulosum

The granular layer of the epidermis, where keratinization begins.

Stratum spinosum

The spiny layer of the epidermis, characterized by desmosome-like junctions between cells.

Stratum germinativum (stratum basale)

The basal layer of the epidermis, where cells are actively dividing and push cells up to the surface.

Papillary layer

The thin, superficial layer of the dermis, lying just below the epidermis, containing looping blood vessels and nerve endings (Meissner’s corpuscles).

Reticular layer

The deeper and thicker layer of the dermis, making up 80% of its thickness, composed of parallel bundles of collagen fibers.

Pacinian corpuscles

Deep touch/pain receptors found in the hypodermis.

Pigmentation

The result of the presence or absence of melanin granules, affecting skin and hair color, controlled by melanocyte-stimulating hormone (MSH).

Paw pads

Tough, thick layers of fat and connective tissue on the feet, containing exocrine sweat glands and lamellar corpuscles, covered by conical papillae.

Planum nasale

The top of the nose in cats, pigs, sheep, and dogs, usually pigmented and aglandular (except in some species like sheep, pigs, cows).

Planum nasolabiale

The muzzle in cows and horses.

Ergots

Dark, horny structures on the legs of equine family members, thought to be vestiges of digits, buried in the caudal hairs of the fetlock.

Chestnuts

Dark, horny structures on the legs of equine family members, thought to be vestiges of digits, found on the inside of each leg at the carpus and tarsus.

Cutaneous pouches (in sheep)

Infoldings of skin containing fine hair, sebaceous, and oil glands, found in infraorbital, interdigital, and inguinal locations.

Hair

An essential integumentary structure for survival, functioning in body temperature maintenance and protection/camouflage.

Medulla (hair)

The innermost of the three concentric layers of a hair strand.

Cortex (hair)

The middle layer of a hair strand, surrounding the medulla.

Cuticle (hair)

The outermost, scalelike layer of a hair strand.

Primary hairs (guard hairs)

Straight or arched hairs that are thicker and longer than secondary hairs, dominating in a complex hair follicle.

Secondary hairs (wool-type hairs)

Softer and shorter hairs than primary hairs.

Tactile hairs (sinus hairs/whiskers)

Specialized hairs used as probes and feelers.

Arrector pili muscle

A small, smooth muscle attached to each hair follicle, innervated by the sympathetic nervous system, whose contraction pulls the hair erect.

Sebaceous glands

Glands located in the dermis that produce sebum and lanolin, often emptying into hair follicles.

Sweat glands (sudoriferous glands)

Glands that produce a watery, transparent liquid to help cool the body through evaporation.

Eccrine sweat glands

Sweat glands that empty directly onto the surface of the skin.

Apocrine sweat glands

Sweat glands that empty into hair follicles.

Sebum

An oily, lipid substance manufactured by sebaceous glands, which coats hair and skin, traps moisture, keeps skin and hair soft/pliant/waterproof, and reduces infection risk.

Tail glands

An oval region at the dorsal base of the tails of most dogs and cats, containing especially large apocrine and sebaceous glands with coarse, oily hairs, assisting in animal identification.

Anal sacs

Reservoirs for malodorous secretions, lined with sebaceous and apocrine glands, expressed during defecation or when an animal is frightened.

Claws

Hard outer coverings of the distal digits, typically non-retractable (except in most cats), used for traction, defense, and catching prey.

Dewclaws

Evolutionary remnants of digits, such as the first digit in dogs or the second and fifth digits in cows, pigs, and sheep.

Kwik (quick)

The live dermis within a claw or nail, containing blood supply and nerve endings.

Hoof (Ungula)

The horny outer covering of the digits of some animals (ungulates).

Corium (hoof)

The inner layer of the hoof, a modified dermis, on which the hoof rests.

Wall (hoof)

The convex, external portion of the equine hoof, divided into toe, quarters, and heel.

Sole (hoof)

The plantar or palmar surface of the equine hoof.

White line (hoof)

A visible junction between the wall and the sole of the equine hoof.

Frog (hoof)

A triangular horny structure on the plantar or palmar surface of the equine hoof, containing a central sulcus.

Digital cushion (hoof)

A highly elastic connective tissue structure located beneath the frog and behind the distal phalanx in the equine hoof.

Lateral cartilages (hoof)

Cartilaginous structures on either side of the digital cushion, supporting the hoof.

Horns

Masses of horny keratin that grow continuously, are not sex-related, and are epidermal in origin.

Antlers

Bony protuberances from the skull, primarily found on males, dermal in origin, shed annually, and lack a central core and internal blood supply (except during velvet skin growth).