Chapter 4,5,6,9 A&P Lecture PDF

Chapter 4 A&P (glands, cell junctions, inflammation) Glands 4.1 Four Types of Tissue (2 of 3) Epithelial tissue –Covers exposed surfaces –Lines internal passageways –Forms glands Epithelial tissue includes epithelia and glands –Epithelia (singular, epithelium) ▪Layers of cells covering interna...

Chapter 4 A&P (glands, cell junctions, inflammation) Glands 4.1 Four Types of Tissue (2 of 3) Epithelial tissue –Covers exposed surfaces –Lines internal passageways –Forms glands Epithelial tissue includes epithelia and glands –Epithelia (singular, epithelium) ▪Layers of cells covering internal or external surfaces –Glands ▪Structures that produce fluid secretions 4.3 Classification of Epithelia Cuboidal epithelia –Simple cuboidal epithelia ▪Secretion and absorption ▪Glands and portions of kidney tubules –Stratified cuboidal epithelia ▪Relatively rare ▪Ducts of sweat glands and mammary glands Glandular epithelia- a type of tissue that produces and releases substances in the body –Glands are collections of epithelial cells that produce secretions –Endocrine glands- through the bloodstream ▪Release hormones that enter bloodstream ▪No ducts –Exocrine glands- on the skin ▪Produce exocrine secretions ▪Discharge secretions through ducts onto epithelial surfaces Gland structure –Unicellular glands –Multicellular glands Unicellular glands –Goblet cells are unicellular exocrine glands –Endocrine glands ▪In epithelia of intestines ▪Secrete mucin, which mixes with water to form mucus Multicellular exocrine glands are classified by Examples of multicellular exocrine glands include: Sweat glands: Also known as sudoriferous glands Oil glands: Also known as sebaceous glands Salivary glands: Contain serous cells that secrete a protein-rich fluid, and mucous cells that secrete mucins Multicellular glands are tubular Simple glands: Have a single, continuous duct Compound glands: Have branched ducts Tubular glands: Have tubular secretory units with straight or coiled tubes  Merocrine secretion –Released by secretory vesicles (exocytosis) –Example: merocrine sweat glands Apocrine secretion –Released by shedding cytoplasm –Example: mammary glands Holocrine secretion –Released by cells bursting, killing gland cells –Gland cells replaced by stem cells –Example: sebaceous glands Types of secretions produced by exocrine glands –Serous glands ▪Watery secretions –Mucous glands ▪Secrete mucins –Mixed exocrine glands ▪Both serous and mucous Cell Junctions A characteristic of epithelia is cellularity (cell junction) cellularity is a characteristic of epithelial tissue, which is made up of cells that are tightly bound together with little to no space between them Intercellular connections –Cell junctions! ▪Form bonds with other cells or extracellular material 1.Gap junctions- allow rapid communication, held together by connexons, allow small molecules and ions to pass, coordinate contractions in heart muscle 2.Tight junctions- between two plasma membranes,adhesions belt attaches to terminal web, prevent passage of water and solutes keep enzymes, wastes, and acids in the lumen of the digestive tract 3.Desmosomes → next slide! Intercellular connections CONTINUED 3.Desmosomes- CAMs and proteoglycans link opposing plasma membranes Spot desmosomes- tie cells together, allow bending and twisting, Hemidesmosomes- attach cells to the basement membrane Inflammation 4.11 Tissue Injuries and Repair (1 of 4) Learning Outcomes: Describe how injuries affect the tissues of the body. Tissues respond to injury in two stages 1.Inflammation (inflammatory response) 2.Regeneration: to restore normal function Inflammatory response –Can be triggered by: ▪Trauma (physical injury) ▪Infection (the presence of pathogens) –Damaged cells release prostaglandins, proteins, and potassium ions –Damaged connective tissue activates mast cells Process of inflammation –Lysosomes release enzymes that destroy the injured cells and attack surrounding tissues –Tissue destruction is called: necrosis ▪Begins several hours after injury Necrotic tissues and cellular debris (pus) accumulate in the wound –Abscess is pus trapped in an enclosed area The ability to regenerate varies among tissues –Epithelia, connective tissues (except cartilage), and smooth muscle regenerate well –Skeletal muscle, cardiac muscle, and nervous tissues regenerate poorly, if at all –Damaged cardiac muscle cells are replaced by fibrous tissue through fibrosis  Chapter 5 A&P (Skin repair and aging, types of perspiration, pigmentation, apocrine vs merocrine, thermoregulation) Skin repair 5.2 The Dermis Skin damage –Loss of skin turgor is caused by ▪Dehydration (reversible) ▪Aging ▪Hormones ▪UV radiation –Excessive distortion of skin from pregnancy or weight gain may cause stretch marks Aging 5.10 Aging and the Integumentary System Learning Outcomes: Summarize the effects of aging on the skin. Effects of aging on skin –Epidermis thins –Number of dendritic cells decreases –Vitamin D3 production declines –Melanocyte and glandular activities decline –Blood supply to dermis is reduced –Function of hair follicles declines –Dermis thins and elastic fiber network shrinks –Sex-specific hair and body fat distribution fades –Repair rate slows Perspiration 5.1 Epidermis (11 of 12) Water is lost from skin in two ways –Insensible perspiration ▪Water diffuses across stratum corneum and evaporates from skin ▪500 mL per day ▪Rate increases if stratum corneum is damaged (ex: from burns) –Sensible perspiration ▪Water excreted by sweat glands  Apocrine sweat glands –Found in armpits, around nipples, and in pubic region –Secrete products into hair follicles via merocrine secretion –Produce sticky, cloudy secretions ▪Nutrient source for bacteria, which cause odors –Surrounded by myoepithelial cells ▪Squeeze secretions out of glands in response to hormonal or nervous signals  Eccrine(merocrine) sweat glands –Coiled, tubular glands that discharge directly onto skin surface (sensible perspiration) –Widely distributed on body surface ▪Especially on palms and soles –Secretions are 99 percent water plus salt, etc. –Functions include ▪Cooling surface of skin to reduce body temperature ▪Excreting water and electrolytes ▪Providing protection from environmental hazards –Eccrine sweat glands ▪Controlled precisely; sweating may occur locally Pigmentation 5.4 Skin Color (2 of 5) Melanin –Red-yellow or brown-black pigment –Produced by melanocytes –Stored in intracellular vesicles (melanosomes) ▪Transferred to keratinocytes ▪Dark-skinned people have large, numerous melanosomes –Protects skin from ultraviolet (UV) radiation ▪Small amounts of UV radiation are beneficial ▪Too much can damage DNA and cause cancer  Carotene –Orange-yellow pigment –Found in orange vegetables –Accumulates in epidermal cells, deep dermis, and subcutaneous layer –Can be converted to vitamin A, required for ▪Maintenance of epithelia ▪Synthesis of photoreceptor pigments in eye  Blood flow and oxygenation influence skin color –Hemoglobin is bright red when bound to oxygen ▪When blood vessels dilate from heat, skin reddens ▪When blood flow to skin decreases, skin pales –Hemoglobin turns dark red when oxygen is released ▪Can result in cyanosis (bluish skin) ▪May be caused by extreme cold, heart failure, severe asthma, etc.  Illness and skin color –Jaundice ▪Buildup of bile produced by liver ▪Skin and whites of eyes may turn yellow –Pituitary tumor ▪Excess MSH increases production of melanin –Addison’s disease ▪Causes pituitary gland to release excess ACTH, which has an effect similar to MSH –Vitiligo ▪Loss of melanocytes causing loss of color Apocrine vs Merocrine Apocrine and merocrine glands are both types of exocrine glands, which secrete products through ducts. The main differences between the two are how they release their secretions, their location, and the composition of their secretions: Release method Apocrine glands release their secretions by pinching off parts of the cell membrane, while merocrine glands release their secretions through exocytosis, which doesn't damage the cell. Location Apocrine glands are found deep within the skin, while merocrine glands are found on the surface of the skin. Secretion composition Apocrine gland secretions are thicker and contain nutrients for skin bacteria, while merocrine gland secretions contain water and sodium chloride. SALTY Thermoregulation Thermoregulation is the process by which an organism maintains its body temperature within a certain range, even when the external temperature is different. It's a key part of homeostasis, which is the state of dynamic stability within an organism's internal conditions. Here are some key points about thermoregulation: How it works The hypothalamus is the body's thermostat, and it regulates temperature homeostasis by balancing heat production and heat loss. The hypothalamus contains temperature sensors that receive information from the body's peripheral and central thermoreceptors. These sensors detect surface temperatures and core temperatures, respectively. –Thermoregulation ▪The main function of sensible perspiration ▪Eccrine sweat glands work with cardiovascular system to regulate body temperature  Chapter 6 A&P (bone function, compact vs spongy bone, long bone 4 cell types: periosteum, endosteum, intramembranous, exercise effect on bone, hormones, calcium, parathyroid hormone vs calcitonin) Bone function  Primary functions of the skeletal system –Support –Storage of minerals and lipids –Blood cell production –Protection –Leverage Compact vs Spongy bone  Osteon—cylindrical functional unit of compact bone Compact bone is denser and stronger than spongy bone  Spongy bone lacks osteons Osteons- Osteons serve as the functional unit of bone. Their thick lamellar rings provide mechanical support and strength to bone –Red bone marrow ▪Forms blood cells ▪Contains blood vessels that supply nutrients to osteocytes by diffusion –Yellow bone marrow ▪Stores fat Long bone Mineral storage Long bones store minerals like calcium, phosphorus, sodium, and magnesium, which are essential for regulating physiological activities. Structure and support Long bones provide strength, structure, and stability to the skeleton. Periosteum  Periosteum—membrane that covers outside of bones –Except within joint cavities –Outer, fibrous layer and inner, cellular layer –Fibers are interwoven with those of tendons –Perforating fibers—fibers that become incorporated into bone tissue ▪Increase strength of attachments Endosteum  Endosteum—incomplete cellular layer that lines medullary cavity –Active during bone growth, repair, and remodeling –Covers trabeculae of spongy bone –Lines central canals of compact bone –Consists of flattened layer of osteogenic cells Intramembranous Intramembranous ossification is a process that develops bones from sheets of connective tissue membranes, and is involved in the formation of certain flat bones of the skull, the clavicles, and some irregular bones Exercise effect on bone  Effects of exercise on bone –Mineral recycling allows bones to adapt to stress –Heavily stressed bones become thicker and stronger –Exercise, particularly weight-bearing exercise, stimulates osteoblasts Bone degeneration –Bone degenerates quickly –Up to one-third of bone mass can be lost in a few weeks of inactivity Hormones 6.7 Exercise, Nutrition, and Hormones (4 of 4) Nutritional and hormonal effects on bone –Growth hormone and thyroxine stimulate bone growth –Sex hormones ▪Estrogen and testosterone stimulate osteoblasts –Parathyroid hormone and calcitonin maintain calcium ion homeostasis Parathyroid hormone and calcitonin maintain calcium ion homeostasis Parathyroid hormone (PTH) –Produced by parathyroid glands in neck –Increases blood calcium ion levels by ▪Stimulating osteoclast activity (indirectly) ▪Increasing intestinal absorption of calcium by enhancing calcitriol secretion by kidneys ▪Decreasing calcium excretion by kidneys Calcium  Characteristics of bone –Dense matrix due to deposits of calcium salts –Osteocytes (bone cells) within lacunae organized around blood vessel –Canaliculi ▪Narrow passageways that allow for exchange of nutrients, wastes, and gases –Periosteum ▪Covers outer surfaces of bones (except at joints) ▪Consists of outer fibrous and inner cellular layers Bone development –Ossification (osteogenesis)—bone formation –Calcification—deposition of calcium salts ▪Occurs during ossification –Two forms of ossification ▪Endochondral ossification ▪Intramembranous ossification –Some human bones grow until about age 25 Parathyroid hormone vs calcitonin Parathyroid hormone (PTH) and calcitonin are hormones that work together to regulate calcium levels in the blood Parathyroid hormone (PTH) Secreted by the parathyroid glands in the neck, PTH increases calcium levels in the blood by activating osteoclasts, which break down bone to release calcium. PTH also helps the kidneys absorb calcium Calcitonin Produced by the C-cells in the thyroid gland, calcitonin decreases calcium levels in the blood by inhibiting osteoclasts and increasing the amount of calcium excreted in urine The levels of both PTH and calcitonin are controlled by blood calcium levels: PTH: The parathyroid glands release PTH when blood calcium levels are low. Calcitonin: The thyroid gland releases calcitonin when blood calcium levels are high. Chap 9 Functional classifications of joint  Two classification schemes –Structural (anatomy) –Functional (range of motion) Joint structure determines function  Structural classifications –Fibrous –Cartilaginous –Bony –Synovial Functional classifications –Synarthrosis (immovable joint) –Amphiarthrosis (slightly movable joint) –Diarthrosis (freely movable joint) Synarthrosis (immovable joint) –Very strong –Edges of bones may touch or interlock –May be fibrous or cartilaginous –Four types of synarthrotic joints ▪Suture ▪Gomphosis ▪Synchondrosis ▪Synostosis  Synovial joints (diarthroses) –Freely movable joints –At ends of long bones –Surrounded by joint capsule (articular capsule) ▪Contains synovial membrane –Synovial fluid from synovial membrane ▪Fills joint cavity –Articular cartilage covers articulating surfaces ▪Prevents direct contact between bones Synovial joints  Synovial joints are mobile but relatively weak Stabilized by accessory structures –Cartilages and fat pads –Ligaments –Tendons –Bursae  Tendons –Attach to muscles around joint Bursae –Small pockets of synovial fluid –Cushion areas where tendons or ligaments rub against other tissues Factors that stabilize synovial joints –Prevent injury by limiting range of motion ▪Collagen fibers of joint capsule and ligaments ▪Shapes of articulating surfaces and menisci ▪Other bones, muscles, or fat pads ▪Tendons attached to articulating bones Sprain- ligament with torn fibers Movements, Triaxial etc  Movements are described in terms that reflect the –Plane or direction of movement –Relationship between structures Planes of movement –Monaxial—1 plane (e.g., elbow) –Biaxial—2 planes (e.g., wrist) –Triaxial—3 planes (e.g., shoulder)  Saddle joint –Articular faces fit together like a rider in a saddle –Biaxial Pivot joint –Rotation only –Monaxial Ball-and-socket joint –Round head in a cup-shaped depression –Triaxial