5 Flashcards
What is tissue?
Tissue is a group of similar cells that perform a common function.
What are the four primary types of tissue in the body?
The four primary types of tissue are epithelial, connective, muscle, and nervous.
What is epithelial tissue?
Epithelial tissue is composed of tightly packed cells that form a continuous layer, which covers and lines body surfaces and organs.
What are the two main types of epithelial tissue and what are their functions?
The two main types of epithelial tissue are coverings and linings and glandular. Coverings and linings protect, absorb, secrete, and excrete. Glandular epithelium produces and secretes substances.
What are the shapes of epithelial cells and what are their functions?
The shapes of epithelial cells include squamous (thin and flat), cuboidal (cube-shaped), and columnar (tall and column-like). Squamous cells allow for rapid diffusion, cuboidal cells secrete and absorb, and columnar cells secrete mucus and absorb nutrients.
What is connective tissue?
Connective tissue supports, protects, and binds organs. It is the most abundant and diverse type of tissue in the body.
What are the three types of fibers found in connective tissue and what are their functions?
The three types of fibers found in connective tissue are collagen (strong and flexible), elastic (stretchy), and reticular (fine, branching fibers that form a network). They provide strength, elasticity, and support.
What is muscle tissue?
Muscle tissue contracts to produce movement.
What are the three types of muscle tissue and where are they found?
The three types of muscle tissue are skeletal (attached to bones), cardiac (found only in the heart), and smooth (found in the walls of hollow organs).
What is nervous tissue?
Nervous tissue contains cells that transmit and receive electrical impulses, allowing for communication between different parts of the body.
What are the two types of cells found in nervous tissue and what are their functions?
The two types of cells found in nervous tissue are neurons (transmit and receive electrical signals) and neuroglia (support and protect neurons).
What is a tissue membrane?
A tissue membrane is a thin layer of tissue that covers and lines body surfaces and organs.
What are the four types of tissue membranes and where are they found?
The four types of tissue membranes are mucous (lines body cavities that open to the exterior), serous (lines body cavities that do not open to the exterior), cutaneous (covers the body surface), and synovial (lines joint cavities).
What is the difference between endocrine and exocrine glands?
Endocrine glands secrete hormones directly into the bloodstream, while exocrine glands secrete substances into ducts that lead to body surfaces or organs.
What is skeletal muscle?
Skeletal muscle is a type of striated muscle that is attached to bones and responsible for voluntary movement.
What is a muscle fiber?
A muscle fiber is a single, multinucleate cell that makes up skeletal muscle tissue.
What is a myofibril?
A myofibril is a cylindrical structure within a muscle fiber that contains contractile proteins called actin and myosin.
What is a sarcomere?
A sarcomere is the smallest functional unit of a muscle fiber, consisting of overlapping actin and myosin filaments.
What is the sliding filament theory?
The sliding filament theory is the explanation for how muscle contraction occurs. It states that the actin and myosin filaments slide past each other, causing the sarcomere to shorten.
What is the neuromuscular junction?
The neuromuscular junction is the point where a motor neuron meets a skeletal muscle fiber. It is the site of communication between the nervous system and the muscular system.
What is the role of acetylcholine in muscle contraction?
Acetylcholine is a neurotransmitter that is released by motor neurons at the neuromuscular junction. It binds to receptors on the muscle fiber, causing depolarization and muscle contraction.
What is muscle tension?
Muscle tension is the force exerted by a contracting muscle. It can be measured in pounds or newtons.
What is muscle tone?
Muscle tone is the continuous, low-level contraction of skeletal muscle fibers. It helps to maintain posture and stabilize joints.
What is muscle fatigue?
Muscle fatigue is the decline in muscle tension and/or the inability to maintain a given level of muscle tension. It can be caused by factors such as depletion of energy stores or accumulation of waste products in the muscle.
What are the two layers of the skin?
The two layers of the skin are the epidermis and dermis.
What is the epidermis?
The epidermis is the outermost protective shield of the body composed of epithelial cells.
What is the dermis?
The dermis is the underlying layer of the skin, making up the bulk of the skin and composed mostly of dense connective tissue.
What is the subcutaneous tissue?
The subcutaneous tissue, also known as the hypodermis or superficial fascia, is a layer of adipose and areolar connective tissue that lies just deep to the skin. It is not part of the skin but shares some of the skin’s protective functions and anchors the skin to underlying structures.
What is the tissue type composing the epidermis?
The epidermis is a keratinized stratified squamous epithelium.
What are the four distinct cell types found in the epidermis?
The four distinct cell types found in the epidermis are keratinocytes, melanocytes, dendritic cells, and tactile epithelial cells.
What is the chief role of keratinocytes in the epidermis?
The chief role of keratinocytes in the epidermis is to produce keratin, the fibrous protein that helps give the epidermis its protective properties.
What is the role of melanocytes in the epidermis?
Melanocytes in the epidermis synthesize the pigment melanin and transfer it to nearby keratinocytes, forming a pigment shield that protects the nucleus from the damaging effects of ultraviolet (UV) radiation in sunlight.
What are dendritic cells in the epidermis?
Dendritic cells in the epidermis are star-shaped cells that ingest foreign substances and are key activators of our immune system
What are the major layers of the epidermis in thick skin?
The major layers of the epidermis in thick skin, from deep to superficial, are stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, and stratum corneum.
What is the difference between thick and thin skin?
In thick skin, the epidermis consists of five layers, including the stratum lucidum, and covers areas subject to abrasion. In thin skin, the epidermis is thinner and does not have a stratum lucidum, and covers the rest of the body.
What are the functions of bones?
Bones provide support for the body, protect internal organs, assist in movement, store and release minerals and fat, and produce blood cells.
What is ossification?
Ossification is the process by which bone forms. It begins in the embryo and continues until early adulthood.
What are the two types of ossification?
The two types of ossification are intramembranous ossification and endochondral ossification.
What is intramembranous ossification?
Intramembranous ossification is the process by which bone forms directly from mesenchymal cells. It occurs in flat bones such as the skull bones.
What is endochondral ossification?
Endochondral ossification is the process by which bone forms from hyaline cartilage. It occurs in most bones of the body.
What are the two types of bone tissue?
The two types of bone tissue are compact bone and spongy bone.
What is compact bone?
Compact bone is dense and strong bone tissue that forms the outer layer of bones.
What is spongy bone?
Spongy bone is less dense bone tissue that is found in the interior of bones
What are the two main types of bone cells?
The two main types of bone cells are osteoblasts and osteoclasts.
What are osteoblasts?
Osteoblasts are bone-forming cells that secrete the matrix of bone.
What are osteoclasts?
Osteoclasts are bone-resorbing cells that break down bone tissue.
What is bone remodeling?
Bone remodeling is the process by which bone is continuously broken down and rebuilt. It is important for maintaining bone strength and repairing damage.
What is the function of the sarcoplasmic reticulum in a muscle cell?
The sarcoplasmic reticulum stores and releases calcium ions for muscle contraction.
What is a muscle twitch?
A muscle twitch is a single contraction-relaxation cycle in a muscle fiber in response to a single action potential.
What is the difference between a muscle twitch and a tetanic contraction?
A muscle twitch is a brief, isolated contraction, while a tetanic contraction is a sustained contraction resulting from high-frequency stimulation of a muscle fiber.
What is the difference between isotonic and isometric contractions?
Isotonic contractions result in movement of a load, while isometric contractions do not result in movement of a load but instead increase tension in a muscle.
What is muscle tone?
Muscle tone is the state of partial contraction that keeps muscles firm and ready to respond.
What is muscle fatigue?
Muscle fatigue is the decline in muscle tension as a result of previous contractile activity.
What causes muscle soreness after exercise?
Muscle soreness after exercise is caused by microscopic tears in muscle fibers and the resulting inflammation and repair processes.
What is the difference between slow-twitch and fast-twitch muscle fibers?
Slow-twitch muscle fibers contract more slowly and have more endurance, while fast-twitch muscle fibers contract more quickly and are used for more powerful, quick movements.
What is the difference between aerobic and anaerobic respiration in muscle cells?
Aerobic respiration uses oxygen to produce ATP and is more efficient, while anaerobic respiration produces ATP without oxygen and is less efficient but can provide energy more quickly.
What is the role of creatine phosphate in muscle contraction?
Creatine phosphate donates a phosphate group to ADP to quickly produce ATP for muscle contraction during short bursts of activity.
What is the function of the integumentary system?
The integumentary system protects the body from external damage, regulates body temperature, and helps to synthesize vitamin D.
What are the layers of the skin?
The layers of the skin are the epidermis, dermis, and hypodermis (subcutaneous layer).
What is the epidermis?
The epidermis is the outermost layer of the skin, composed primarily of stratified squamous epithelium.
What is the dermis?
The dermis is the layer of skin beneath the epidermis, composed of connective tissue with embedded blood vessels, nerves, and other structures.
What is the hypodermis?
The hypodermis is a layer of connective tissue and adipose (fat) tissue beneath the dermis.
What are the cells found in the epidermis?
The cells found in the epidermis include keratinocytes, melanocytes, and Langerhans cells.
What is the function of keratinocytes?
Keratinocytes produce keratin, a fibrous protein that gives the skin its strength and durability.
What is the function of melanocytes?
Melanocytes produce the pigment melanin, which helps to protect the skin from the harmful effects of ultraviolet (UV) radiation.
What is the function of Langerhans cells?
Langerhans cells are a type of immune cell that helps to protect the skin from infection and other foreign invaders.
What is the structure of the dermis?
The dermis is composed of two layers: the papillary layer, which is made up of loose connective tissue and contains blood vessels and nerve endings, and the reticular layer, which is made up of dense connective tissue and contains collagen and elastic fibers.
What is a sarcomere?
A sarcomere is the functional unit of a muscle fiber, consisting of overlapping thick and thin filaments.
What is the sliding filament model of muscle contraction?
The sliding filament model of muscle contraction states that during contraction, the thin filaments slide past the thick filaments, causing the sarcomere to shorten.
What is the role of calcium ions in muscle contraction?
Calcium ions bind to troponin, causing a conformational change that exposes the active sites on the thin filaments, allowing the myosin heads to bind and initiate muscle contraction.
What is the role of ATP in muscle contraction?
ATP is required for myosin heads to detach from actin and reset for the next contraction cycle.
What is the role of the motor neuron in muscle contraction?
The motor neuron releases acetylcholine at the neuromuscular junction, which stimulates the muscle fiber to contract.
What is the role of the neuromuscular junction in muscle contraction?
The neuromuscular junction is the synapse between a motor neuron and a muscle fiber, where acetylcholine is released to stimulate muscle contraction.
What is the role of the sarcoplasmic reticulum in muscle contraction?
The sarcoplasmic reticulum stores and releases calcium ions, which are required for muscle contraction.
What is the difference between isometric and isotonic contractions?
Isometric contractions involve muscle tension without a change in muscle length, while isotonic contractions involve a change in muscle length without a change in muscle tension.
What is muscle fatigue?
Muscle fatigue is the decline in muscle performance due to prolonged or intense muscle activity.
What is the difference between slow-twitch and fast-twitch muscle fibers?
Slow-twitch muscle fibers contract slowly and are fatigue-resistant, while fast-twitch muscle fibers contract quickly and are more prone to fatigue.