Exam 2 Study Guide - Human Anatomy and Physiology I | BSCI 201, Study notes of Physiology

Download Exam 2 Study Guide - Human Anatomy and Physiology I | BSCI 201 and more Study notes Physiology in PDF only on Docsity! BSCI 201 Review Sheet for Exam 2 Gloribel Le A. The Integumentary system: Name and describe all the strata in the epidermis of a thin layer and a thick layer. Stratum Corneum - superficial stratum -Superficial layer of epidermis -Composed of 20-30 layers of dead, flat cells -**Dead cells are impregnated with glycolipids and keratin to provide a tough, durable, waterproof “coat” -Replaced every 3 to 4 weeks Stratum Lucidum (thick) - thin, translucent layer of dead cells Stratum Granulosum – contains granules -Composed of 3 to 5 layers of cells -Cells contain 2 types of granules:  Lamellated granules- contain Glycolipids- the lipids make the epidermis water- proof  Keratohyaline granules- contain the tough, insoluble protein, Keratin, which makes the epidermis tough and abrasive-resistant Stratum Spinosum – contains tonofilaments -Several layers of cells -Cells are connected by desmosomes – hold cells together which causes the cells to aappear “spiny” during histological preparation -Cells contain intermediate filaments  Tonofilaments -Epidermal dendritic cells- Langerhans’ cells in the stratum spinosum act as macrophages to engulf and digest pathogens Stratum Basale – deepest stratum -Single layer of cells: Keratinocytes, Melanocytes, Merkel cells  Keratinocytes: mitotically active producing cells for superficial layers  Gives the name: Stratum Germinativum Melanocytes: **produce the pigment MELANIN contained in mealnosomes- which accumulate on superficial surface of the keratinocytes in stratum basale. Melanin acts as a chemical shield to protect the nuclei of the keratinocytes from the harmful effects of UV radiation in sunlight. Melanin gives skin its color. In sun/tanning, these cells make extra melanin to protect you from getting burned by UV rays.  Merkel Cells: CELLS ARE NOT TOUCH RECEPTORS: at epidermal-dermal junction associate with free nerve endings to form Merkel Discs which act as touch receptors 1 Describe: tonofilaments, Langerhan’s cells, lamellated granules, keratohyaline granules Tonofilaments – the intermediate filaments of Stratum Spinosum Langerhan’s cells – epidermal dendritic cells in the Stratum Spinosum that act as macrophages to engulf and digest pathogens Lamellated granules – in the Stratum Granulosum; contain glycolipids to make a waterproof coat for the epidermis Keratohyaline granules – in the Stratum Granulosum; contain the tough, insoluble protein keratin which makes the epidermis tough, and abrasive resistant Name and describe the two layers in the dermis The Papillary Layer:  Composed of areolar CT  Surface has peg-like projections called Dermal Papillae – houses blood capillaries and nerve endings and Meissner’s corpuscles which act as touch receptors  In thick skin, the surface of the papillae are supported by mounds called Dermal Ridges which form impressions on the epidermal surface Epidermal Ridges (= friction ridges)  increase friction and enhance gripping  Pattern of epidermal ridges is genetically determined and therefore unique to individuals  acts as the basis for finger-printing  Contains the Meissner’s Corpuscles- act as touch receptors The Reticular Layer of the Dermis  Deeper layer- 80% of the dermis  Composed of dense irregular CT  Contains the touch receptors for deep pressure – Pacinian Corpuscles  Cleavage (tension) illness- areas of the reticular layer w/ less collagen bundles  Incisions made parallel to the cleavage lines gape(?) less and therefore heal faster  Striae (stretch marks) – indicate dermal tearing replaced by silvery white scars Describe the following: Meissner’s corpuscles, Pacinian corpuscles, Merkel discs Meissner’s corpuscles – papillary layer of the dermis; act as touch receptors Pacinian corpuscles – located in the reticular layer of dermis and respond to deep pressure place on skin Merkel discs – epidermal-dermal junctions; act as light touch receptors Name and discuss the function of the accessory skin structures. What is acid mantle? *Acid mantle – acidic pH (4-6) of sweat prevents microbial growth on surface of skin Sweat Glands – also known as suderiferous glands  Simple coiled tubular multicellular exocrine glands  2 types: Eccrine and Apocrine o Eccrine Sweat Glands: 3 million per person  Abundant in palms, soles, and forehead  SECRETE SWEAT  Use the MEROCRINE MODE of secretion  “merocrine sweat glands” 2 o Spongy bone tissue in epiphyses contains red bone marrow in between trabeculae  hematopoeisis – process by which the blood cells and platelets are produced o The ends of the epiphyses are covered by thin layers of hyaline cartilage called ARTICULAR CARTILAGES  2 epiphyses are diaphysis o Diaphysis: composed of a thick collar of compact bone surrounding a cavity called MEDULLARY CAVITY (contains bone marrow)  Medullary cavity, child: RED bone marrow  produce blood cells and platelets  Medullary cavity, adult: YELLOW bone marrow does not produce blood cells and platelets; infiltrated with fat  Periosteum: double-layered membrane attached to surface of long bones by collagenous fibers- Sharpey’s Fibers o Outer fibrous layer- composed of DENSE IRREGULAR CT = highly vascularized  Blood vessels extend from the fibrous layer into the bone to provide nutrients & remove metabolic wastes o Inner osteogenic layer- composed of 2 cell types:  Osteoblasts- derived from mesenchyme; secrete bone tissue  Osteoclasts- cause bone resorption (breakdown)  Endosteum: a single-layer membrane that covers the surfaces of trabeculae in spongy bone & lines the internal surface of the medullary cavity, Haversian canals & the canaliculi Name and describe the 2 types of prenatal ossification Ossification: process by which the embryonic skeleton is turned into the bony skeleton  Prenatal (before birth= in uterus): 2 types: o Intramembranous ossification – the starting material is FIBROUS CT membrane derived from mesenchyme.  Bones formed are: cranial (8, paired temporal bones, paired parietal bones, single frontal bone, single occipital bone, single ethmoid bone, single spheroid bone) & clavicles; All of these bones are referred to as MEMBRANOUS bones  all membrane bones are FLAT bones ***Not all flat bones are membrane bones!!! (T or F) o Endochondral ossification – starting material is HYALINE CARTILAGE secreted by chondroblasts derived from mesenchyme  conversion of hyaline cartilage into bone tissue by osteoblasts infiltrating the hyaline cartilage and mineralization of the matrix from semi-solid to a solid matrix  Bones formed are: all bones in the body except the 8 cranial bones and the 2 clavicles; All of these bones are referred to as ENDOCHONDRAL or CARTILAGE bones  After endochondral ossification, hyaline cartilage persists in 2 area in Long Bones: Articular Cartilages & Epiphyseal plates 5  206 Bones in Adult Skeleton  126 in appendicular and 80 in axial; 10 membrane bones and 196 enochondral bones 5 Zones in the epiphyseal plate (from the epiphyseal face to the diaphyseal face) 1. Growth (proliferation zone 2. Hypertrophic zone – old chondrocytes undergo hypertrophy = increase size 3. Calcification zone - DETERIORATION; mineralization of the matrix of the hyaline cartilage occurs  chondrocytes don’t receive any nutrients from the perichondrium; chondrocytes die  matrix of the hyaline cartilage breaks down 4. Ossification zone 5. Resorption zone Name and describe the 2 types of postnatal ossification (bone growth AFTER birth)  Longitudinal (linear) bone growth- occurs ONLY in long bones involving the epiphyseal plates  located @ junctions of the diaphysis and the 2 epiphyses of a long bone o New hyaline cartilage is secreted onto the epiphyseal face on the growth (proliferation) zone of the plate  chondroblast proliferation occurs to increase hyaline cartilage secretion on the epiphyseal plate  Appositional bone growth – occurs in ALL bones ; increases the diameter or thickness o The amount of new bone tissue secreted by the osteoblasts in the osteogenic layer of the periosteum exceeds the slight resorption of bone tissue on the internal surface by osteoclasts in the endosteum; results in thicker, lighter bone Give the function of osteoblasts and osteoclasts in bone remodeling Osteoblasts move into the epiphyseal plates to secrete new bone tissue  the new bone tissue is mineralized/ calcified to form the solid matrix of bone tissue  OSSIFICATION ZONE  The new bone tissue added onto the diaphyseal face = the new hyaline cartilage added onto the epiphyseal face of the epiphyseal plate  WIDTH (diameter) of the epiphyseal plates have NOT changed = epiphyseal plates have shifted = the proximal epiphyseal plates have shifted superiorly; the distal epiphyseal plates have shifted inferiorly  Diaphysis increases; length of the long bone increases As the long bone lengthens, the medullary cavity also lengthens in the RESPORPTIVE zone, osteoclasts resorb bone on the diaphyseal face of the epiphyseal plate (new bone tissue) slightly to increase medullary cavity within the diaphysis Discuss the biological actions of these hormones Growth hormone’s stimulating effect on longitudinal bone growth is INDIRECT. G.h. stimulates the hepatocytes to produce growth factors called INSULINE-LIKE GROWTH FACTORS (IGFs or somatomedins).  IGFs directly stimulate chondroblast proliferation & increase hyaline = longitudinal bone growth Sex steroid hormones (estrogen and testosterone): produced after puberty and synergize with growth hormone to stimulate hepatocytes to produce IGFs & increase chondroblast 6 proliferation  increases hyaline cartilage formation  longitudinal bone growth ; observed in adolescence as “Growth Spurt” As the levels of sex steroid hormone increases to a critical level, the same sex steroid hormones ANTAGONIZE growth hormone in stimulating hepatocytes to release IGFs  IGFs decrease and hyaline cartilage formation decreases Sex steroid hormones stimulate ossification of the epiphyseal plates = exceeds the rate of hyaline cartilage formation by the chondrocytes (IGFs decreasing). Eventually, the entire epiphyseal plates are OSSIFIED = TURNED INTO BONE TISSUE. The complete ossification of epip. Plates in long bones results in EPIPHYSEAL PLATE CLOSURE  Longitudinal bone growth ceases and FINAL height determined Give the stimuli for the release of the following hormones in bone remodeling: a. Parathyroid hormone (PTH) – releases the response of … wake all hormones in negative feedback; corrects stimulus; PTH will stimulate osteoclasts to cause bone resportion, and put calcium in the blood (correcting it); b. 1, 25 dihydroxy vitamin D3 – PTH solicits this guy’s help. c. Calcitonin – stimulates osteoblasts to secrete new bone tissue, using Ca from blood Bone remodeling - coupled reaction of bone formation and bone resportion that occurs throughout life. To maintain a constant bone density: Rate of bone formation = Rate of bone resorption  When bone resorption outpaces bone formation = the bone tissue becomes less dense and appears porous  Osteoporosis;  Post-menopausal women, due to the absence of estrogen, bone resorption increases over bone formation at menopause (ovaries fail to produce estrogen; estrogen inhibits the effect of Parathyroid hormone PTH which stimulates bone resorption)  Purposes for bone remodeling: Calcium homeostasis & To allow for the repair of bone fractures  Hormonal Control of bone remodeling: o Calcium levels are maintained strictly between 9mg – 11mg/100 cc of blood o Total calcium in the adult  1.2 kg (99% is stored in bone tissue as the hydroxyapatites) o Hypocalcemia: Ca levels fall below 9mg/100cc of blood  Stimulates the release of PTH  Stimulates bone resorption by activating osteoclasts  Stimulates Ca absorption from small intestine, however, PTH action in the small intestine is INDIRECT. PTH first stimulates the synthesis of 1, 25-dihydroxyvitamin (Vit D)  DIRECTLY stimulates Ca absorption from the small intestine  PTH directly stimulates Ca reabsorption from tubular fluid inside the kidneys o Hypercalcemia: Ca levels rise above 11mg/100cc of blood  Stimulates the release of Calcitonin 7