BIO 446L 1st Edition Lecture 32 Outline of Last Lecture I. Urinary System contd.a. Nephron Loop of Henlei. Ascending and Descending limbb. Distal convoluted tubulec. Collecting tubules and ductsd. Ureters, bladder, and urethraOutline of Current Lecture I. The Integumentary Systema. Anatomyb. The epidermisi. Stratum layersc. Melanocytesd. The dermisi. Reticular and papillary layerii. Blood supplyiii. Sensory receptorsiv. Hairv. Skin wound repairThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.vi. Sebaceous and sweat glands1. Light cells and dark cellsCurrent Lecture- Integumentary Systemo Anatomy First line of defense against abrasion, UV damage, water loss, thermoregulation- Thermoregulation through blood reservoir and swear Sensations of temperature, pain, pressure, vibration Stratified squamous keratinized epithelia Epidermis dermis subcutaneous (hypodermis with adipose and very vascular) Epidermal ridges= hills and valleys that fit tightly with hills and valleys of dermal layero The epidermis Thick skin on the palms and soles of feet Thin skin everywhere else Keratinocytes= produce keratin, primarily make up the epidermis Melanocytes, Langerhan cells, tactile (Merkel) cells, and antigen presenting cells also compose this layer Stratum corenum- Dead cells on top are oily and water resistant Stratum lucidum- Dead, thick skin, contain some keratin proteins, oily Stratum glandulum- Eosinophillic granules (immune response), cells beginning to die Stratum spinosum- Keratinocytes, mitotic cekks Stratum basalis- Mitotic stem cells, melanocytes Keratin= intermediate fiber- Deposited by spinosum in tonal fibrils—long, strong fibrils linked to desmosomes in cell wall (holds epithelial layers together) Tactile (Merkel) cells—collect granules, sit in synapses with neuron, touch sensors release neurotransmitter fire action potentialo Melanocytes Synthesize melanin with tyrosine in melanocyte Derived from neural crest Form dopa (neurotransmitter) Long processes in basal layer to spinosum Processes= destination for melanosomes- Will contact basal and spinosum cells and phagocytose, which gives the cells color- Transport melanosomes to nucleus with dynein to protect from UV rays Albinism= melanin in hair, skin, eyes is absent- Sensitive to UV lighto The dermis Reticular (dense) layer—not reticular lamina, lower layer, dense irregular connective tissue, elastic fibers, sweat and sebaceous glands, nerve endings- Anchored to epidermis and hypodermis Papillary layer—lymphocytes Intradermal injection- Ex: TB test—causes blister/bubble up due to liquid having little place to go because of density of tissue Blood supply- Subcutaneous later= adipose and blood vessels, subcutaneous injections (ex: Measles shot)- 2 blood vessel networks- Anastomoseso Blood vessels constrict to decrease blood to papillary later to decrease heat loss (and vice versa when too hot)- Hemorrhageo Pale and clammy—skin diverts blood flow elsewhere; where needed Sensory receptors- Unencapsulated= Merkel cells and free nerve endings, hair follicleso Pain, touch, light pressure- Encapsulated= deep pressure, sustained pressure, vibrationo Meissner corpuscles and Tactile cells Two point discrimination, nerve endings in lamellio Pacinian corpuscleso Krause and Ruffinian corpuscles Hair- Dead cells- Follicle= cortex and medullao Connective tissue extending into hair bulbo Epithelial root sheet (from skin surface to hair follicle) Stem cells (same as cells of basal layer) Epidermis follicle If follicle not damaged when burned, the stem cells can replenish by migrating up to higher layerso Corticle root sheet Skin wound repair- See images- Primarily fibroblasts Sebaceous and sweat glands- Sebaceous gland= secrete sebum (oil)- Holocrine secretiono Eccrine (merocrine) and apocrineo Apocrine gland—neurotransmitter is norepinephrineo Eccrine gland—sympathetic post ganglion, secrete Ach to muscarinic receptor (very different for sympathetic neuron)- Dark cells= vesicles with sweat and bacteriocidal cells, secrete sweat- Clear cells= produce
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