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143 Cards in this Set
- Front
- Back
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Functions of the Skin
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1. Resistance to trauma and infection – due to keratin and acid pH
2. Barrier to ultraviolet light 3. Vitamin D synthesis 4. Sensory receptors 5. Thermoregulation through sweating 6. Nonverbal communication |
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Keratinocytes
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– most of the skin cells
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Dendritic (langerhans) cells
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macrophages guard against pathogens
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Tactile (merkel) cells
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receptor cells associated with nerve fibers
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Melanocytes
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synthesize pigment that shield UV
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Stem cells
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undifferentiated cells in deepest layers
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Cells of the Epidermis
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Keratinocytes
Dendritic (langerhans) cells Tactile (merkel) cells Melanocytes Stem cells |
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Stratum Basale
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Single layer cells on basement membrane
Cell types in this layer keratinocytes – divide by mitosis to replace epidermis Melanocytes – make and distribute melanin Merkel cells are touch receptors |
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Stratum Spinosum
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Several layers of keratinocytes
Contains dendritic (Langerhans) cells = macrophages from bone marrow that migrate to the epidermis |
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Stratum Granulosum
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1. 3 to 5 layers of flat keratinocytes
2. Contain keratinohyalin granules - combine with filaments of cytoskeleton to form keratin 3. Produce lipid-filled vesicles that release a glycolipid by exocytosis to waterproof the skin |
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Stratum Lucidum
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1. Thin translucent zone seen only in thick skin
2. Keratinocytes are packed with eleidin, a precursor to keratin 3. Cells have no nucleus or organelles |
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Stratum Corneum
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1. Up to 30 layers of dead, scaly, keratinized cells
2. Surface cells flake off (exfoliate) |
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Life History of Keratinocytes
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1. Produced by stem cells in stratum basale
2. New cells push others toward surface cells grow flat and fill with vesicles 3. Cells fill with keratin - forms water barrier 4. Cells die and exfoliate |
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Dermis
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1. Composition – collagen, elastic, and reticular fibers; fibroblasts
2. Dermal papillae - extensions of the dermis into the epidermis - forms the ridges of the fingerprints 3. Layers Papillary layer Reticular layer |
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Hypodermis
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1. Subcutaneous tissue/ superficial fascia
2. Mostly adipose 3. Functions Energy reservoir Thermal insulation 4. Highly vascular |
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Skin Colors (Pigmentation)
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1. Hemoglobin = red pigment of red blood cells
2. Carotene = yellow pigment concentrates in stratum corneum and fat 3. Melanin = yellow, brown, and black hues; melanin synthesis stimulated by UV radiation |
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Skin Markings
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1. Hemangiomas (birthmarks) - discolored skin caused by benign tumors of dermal blood capillaries
2. Freckles and moles = aggregations of melanocytes 3. Friction ridges leave oily fingerprints on touched surfaces (fingerprints) 4. Flexion creases form after birth by repeated closing of the hand 5. Flexion lines form in wrist and elbow areas |
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Characteristics of Human Hair
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1. Hair (composed of hard keratin)
2. Hair found almost everywhere 3. 3 different body hair types A. lanugo - fine, unpigmented fetal hair B. vellus - fine, unpigmented hair of children and women C. terminal hair - coarse, long, pigmented hair of scalp |
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Structure of Hair and Follicle
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1. Hair is filament of keratinized cells
Hair shaft is above skin Root is within follicle 2. Follicle is tube within the skin Bulb is where hair originates Vascular tissue (papilla) in bulb provides nutrients |
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Color and Texture
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Straight hair is round in cross-section
Curly hair is oval Hair color is due to pigment in the cortex (middle layer of cells in cross-section) |
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Structure of Hair Follicle
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1. Epithelial root sheath
2. Connective tissue root sheath 3. Hair receptors entwine each follicle 4. Piloerector muscle |
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Hair Growth and Loss
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1. Hair cycle = 3 repeating cycles
A. anagen is growth stage (90% of scalp follicles) lasts 6-8 years in young adult B. catagen is shrinking follicle (lasts 2-3 weeks) C. telogen is resting stage (lasts 1-3 months) 2. Thinning or baldness = alopecia 3. Pattern baldness = genetic and hormonal 4. Hirsutism = excessive hair growth |
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Functions of Hair
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1. Heat retention
2. Protection from UV light 3. Beard, pubic and axillary hair indicate sexual maturity and help distribute scents 4. Guard hairs (eyes and ears) 5. Expression of emotions with eyebrows |
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Nails
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1. Derivative of stratum corneum
A. densely packed cells filled with hard keratin 2. Flat nails allow for fleshy, sensitive fingertips 3. Growth occurs when new cells are added by mitosis in the nail matrix 4. Nail plate is visible part of nail |
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Sweat Glands
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1. Filtrate of plasma and some waste products
2. Merocrine glands are simple tubular gland 3. Apocrine glands produce sweat containing fatty acids A. Found only near hair follicles and respond to stress and sex B. Body odor is produced by bacterial action on fatty acids |
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Sebaceous Glands
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1. Oily secretion called sebum that contains broken-down cells
2. Flask-shaped gland with duct that opens into hair follicle |
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Ceruminous Glands
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1. Found only in external ear canal
2. Their secretion combines with sebum to produce earwax A. Waterproof keeps eardrum flexible B. Bitterness repel mites and other pests |
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Mammary Glands
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1. Breasts of pregnant and lactating females have developed mammary glands
A. Modified apocrine sweat gland B. Thicker secretion released by ducts open on the nipple 2. Mammary ridges or milk lines A. 2 rows of mammary glands in most mammals B. Primates kept only anteriormost glands 3. Additional nipples (polythelia) may develop along milk line |
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Skin Cancer
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1. Induced by UV rays of the sun
A. basal cell carcinoma (least dangerous) arises from stratum basale and invades dermis B. squamous cell carcinoma arises from keratinocytes in stratum spinosum metastasis to the lymph nodes can be lethal C. malignant melanoma (most deadly) arises from melanocytes of a preexisting mole ABCD--asymmetry, border irregular, color mixed and diameter over 6 mm |
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UVA, UVB and Sunscreens
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1. UVA and UVB are improperly called “tanning rays” and “burning rays”
2. Both thought to initiate skin cancer 3. Sunscreen may not protect against skin cancer |
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Bone as a Tissue
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1. Connective tissue with a matrix hardened by minerals (calcium phosphate)
2.Continually remodels itself |
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Individual bones consist of
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bone tissue, marrow, blood, cartilage and periosteum
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Functions of Skeletal System
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1. support,
2. protection, 3. movement, 4. electrolyte balances, 5. acid-base balance 6. blood formation |
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Shapes of Bones
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1. Irregular
2. Flat 3. Long 4. Short |
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Long Bones
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levers acted upon by muscles
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Short Bones
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glide across one another in multiple directions
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Flat Bones
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protect soft organs
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Structure of a Long Bone
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1. Compact and spongy bone
2. Marrow cavity 3. Articular cartilage 4. Periosteum |
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Structure of a Flat Bone
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1. External and internal surfaces composed of compact bone
2. Middle layer is spongy bone and bone marrow 3. Skull fracture may leave inner layer of compact bone unharmed |
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Osteoblasts build bone
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by mineralizing organic matter of matrix
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Osteocytes
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are osteoblasts trapped in the matrix they formed
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Cells in lacunae
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connected by gap junctions inside canaliculi
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Osteogenic cells
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(stem cells) in endosteum, periosteum or central canals give rise to new osteoblasts
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Osteoclasts
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1. are bone-dissolving cells
2. Reside in pits that they ate into the bone on the bone’s surface |
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Wolff’s law of bone
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states that bone architecture is determined by mechanical stress
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Bone is constantly
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1. being broken down and rebuilt.
2. Bone is remodeled throughout life. |
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Mineralization
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is crystallization process
A. Osteoblasts produce collagen fibers spiraled the length of the osteon B. Minerals (calcium and phosphate from blood) cover the fibers and harden the matrix |
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Abnormal (ectopic) calcification
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may occur in lungs, brain, eyes, muscles, tendons or arteries (arteriosclerosis)
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Mineral Resorption from Bone
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A. Performed by osteoclasts
B. Hydrogen pumps in membrane secrete hydrogen into space between the osteoclast and bone surface C. Chloride ions follow by electrical attraction D. Hydrochloric acid (pH 4) dissolves bone minerals E. Enzyme (acid phosphatase) digests the collagen |
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Hormone Control of Blood Calcium
A. Calcitriol B. Calcitonin C. PTH |
A. Calcitriol is activated vitamin D; its primary function is raise blood calcium
B. Calcitonin is a thyroid hormone; it lowers blood calcium levels C. Parathyroid hormone (PTH) is secreted by the parathyroid glands; PTH raises blood calcium levels |
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Other Factors Affecting Bone
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Hormones, vitamins and growth factors
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Growth rapid at puberty
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A. hormones stimulate osteogenic cells, chondrocytes and matrix deposition in growth plate
B. girls grow faster than boys and reach full height earlier (estrogen stronger effect) C. males grow for a longer time and taller |
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Growth stops
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(epiphyseal plate “closes”)
A. teenage use of anabolic steroids = premature closure of growth plate and short adult stature |
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Healing of Fractures
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1. Hematoma Formation
2. Soft callus formation 3. Hard callus formation 4. Bone remodeling |
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Osteoporosis
D. treatment for osteroporosis- |
A. Bones lose mass and become brittle
B. Postmenopausal white women at higher risk C. Estrogen inhibits bone resorption D. Estrogen replacement increases risk of breast cancer, stroke and heart disease E. PTH slows bone loss if given daily injection -Forteo increases density by 10% in 1 year -may promote bone cancer F. Best treatment is prevention -- exercise and calcium intake (1000 mg/day) between ages 25 and 40 |
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Hormonal Control of Calcium Balance
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Calcitrol
Calcitonin |
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The Skull
A. Cranial Bones B. Facial Bones C. Sinuses |
A. Cranial bones – surround brain and contact meninges; in humans there are 8
B. Facial bones – support teeth; form nasal cavity and orbit (eye); in humans there are 14 C. Sinuses are air-filled spaces or cavities |
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The Vertebral Column
C. Five regions |
A. 33 bones called vertebrae
B. Discs of fibrocartilage between vertebrae C. Five regions 7 cervical 12 thoracic 5 lumbar 5 sacral (fused) 4 coccygeal (fused) |
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Spinal Curvatures
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A. Cervical curvature develops from lifting of head
B. Lumbar curvature develops from walking upright |
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Vertebral Structure
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Look at slide
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Atlas and Axis
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Look at slide
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Thoracic Cage
A. Contents B. Function |
A. Thoracic vertebrae, sternum, and ribs
B. Protects heart and lungs C. Attachment site for many muscles |
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Bipedalism Adaptations of Limbs
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Look at slide
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Upright Stance in Bipeds
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Look at slide
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Head Position in Bipeds
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Look at slide
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A. Arthrology
B. Kinesiology |
A. study of the joints
B. study of musculoskeletal movement |
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Classification by freedom of movement
A. Diarthrosis B. Amphiarthrosis C. Synarthrosis |
A. Freely moveable
B. Slightly moveable C. Little or no movement |
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Classification by how adjacent bones joined
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Fibrous
Cartilaginous Bony Synovial |
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Range of Motion
B. Determined by |
Degrees (or planes) through which a joint can move
B. 1) Structure of the articular surfaces 2) Strength and tautness of ligament and tendons 3) Action of the muscles and tendons (nervous control) |
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Axis of Rotation
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A. Most joints are monoaxial (one direction) or biaxial (two directions)
B.Shoulder joint has three degrees of freedom/movement |
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Bony Joint
A. also called B. Gap C. Example |
A. Also called synostosis
B. Gap between the two bones become ossified C. Example – frontal and mandibular bones; cranial sutures in elderly |
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Fibrous Joint
A. also called B. collagen C. Example |
A. Also called synarthrosis
B. Collagen spans the space between bones C. Examples are sutures of cranium, teeth in sockets, radius to ulna, and tibia and fibula |
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Cartilaginous Joints
A. Bones joined B. Example C. Movement |
A. Bones are joined by hyaline cartilage (synchondrosis) or fibrocarftilage (symphysis)
B. Examples are rib attachment to sternum and pubic symphysis C. Only slight amount of movement is possible |
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Synovial Joint
A. two bones b. movement |
A. Two bones are separated by a space called a joint cavity
B. Most synovial joints are freely movable |
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Anatomy of a Joint
A. Articular capsule B. Synovial fluid C. Articular cartilage D. Some joints E. Tendon F. Ligament |
A. Articular capsule encloses joint cavity; it is continuous with the periosteum and is lined by synovial membrane
B. Synovial fluid is a slippery fluid in joint space that feeds cartilage C. Articular cartilage is hyaline cartilage that covers the joint surfaces D. Some joints have discs and menisci that absorb shock and distribute forces E. Tendons are connective tissue that attach muscle to bone F. Ligament attaches bone to bone |
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Tendon Sheaths and Bursae
A. Bursae B. Tendon Sheath |
A. Bursa = saclike extension of joint capsule
B. Tendon sheath = cylinders of connective tissue lined with synovial membrane and wrapped around a tendon |
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Levers
A. Bones B. Lever's purpose |
A. Bones work like levers
B. Levers either increase speed or force of movement – allows to accomplish bigger movement with less work |
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A. Flexion
B. Extension C. Hyperextension |
A. Flexion decreases joint angle
B. Extension straightens and returns to anatomical position C. Hyperextension is beyond 180 degrees |
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A. Abduction
B. Adduction |
A. Abduction = movement away from midline
B. Adduction = movement towards midline |
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A. Elevation
B. Depression |
A. Elevation = movement that raises a bone vertically
B. Depression = lowering the bone back to resting position |
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A. Pronation
B. Retraction |
A. Pronation = movement anteriorly on horizontal plane
B. Retraction = posterior movement |
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Circumduction
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Movement in which one end of appendage remains stationary while other end makes a circular motion
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Rotation
A. Movement B. Medial C. Lateral |
A. Movement on longitudinal axis
B. Medial rotation = inward C. Lateral rotation = outward |
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Supination and Pronation
A. Movement B. Supination C. Pronation |
A. Movements of feet and forearms
B. Supination -Palm forward -Raising medial edge of foot C. Pronation -Palm backward -Raising lateral edge of foot |
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Characteristics of Muscle
A. Responsiveness B. Conductivity C. Contractility D.Extensibility E. Elasticity |
A. Responsiveness (excitability) – to chemical signals, electrical signals, and stretch
B. Conductivity – electrical impulse spreads C. Contractility – shortens when stimulated D. Extensibility – can be stretched E. Elasticity – returns to original shape/length |
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A. Muscle cells shorten
B. The shortening of muscle cells C. Three types of muscle |
A. Muscle cells shorten using energy from ATP
B. The shortening of muscle cells can move bones and other body components C. Three main types of muscle Skeletal – voluntary control Cardiac - automatic Smooth - automatic |
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Skeletal Muscle
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A. Voluntary control
B. Attached to bone by connective tissue C. Striated (light and dark bands) D. Composed of specific arrangement of proteins E. Large cells with multiple nuclei |
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Connective Tissue Elements
A. Tendons B.Endomysium C. Perimysium D. Epimysium E. Facia F. Collagen components |
A. Attach muscle to bones = tendons
B. Endomysium – surrounds each muscle fiber C. Perimysium – bundles muscle fibers together D. Epimysium – covers entire muscle E. Fascia – layer of connective tissue between muscles F. Collagen components – help provide recoil - Parallel elastic component - Series elastic component |
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Muscle Fiber
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SLIDE
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Protein Thick and Thin Filaments
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Slide
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Contractile Proteins (actin and myosin)
A. Myosin B. Regulatory Proteins C. Process of reg. proteins |
SLIDE
A. Myosin is arranged in bundles with “heads” pointed outward (thick fiber) B. Troponin and tropomyosin C. calcium binds to troponin causing it to move tropomyoson off the myosin binding site of actin |
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Striations
A. A band, H band B. I band C. Z disc protein D. Sarcomere |
SLIDE
A. A band is thick filament region; light central H band area has no thin filaments B. I band is the thin filament region C. Z disc protein (anchoring site for elastic fibers and thin filament) bisects I band D. Area from Z disc to Z disc = sarcomere |
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Why Do muscles shorten?
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A. Muscles shorten because sarcomeres shorten
B. This happens when the actin and myosin slide over each other, drawing the Z discs closer together C. Neither the thin or thick filaments themselves change length |
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Muscle cells are
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excitable (capable of having action potentials) but don’t contract without nervous input
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Motor neurons have
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(those that control skeletal muscle) have their cell bodies in the brain or spinal cord
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Motor neuron axons
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(somatic nerves) branch near their ends and terminate on individual muscle fibers
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what is a motor unit?
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One motor neuron and all of the muscle fibers it innervates is called a motor unit
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Motor Unit
A. For fine control B. For Strength C. Sustained contraction |
A. For fine control, each nerve controls fewer fibers
B. For strength, each nerve controls hundreds of fibers C. Sustained contraction of a muscle occurs by rotating motor units (some on, some off then switch) |
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The Neuromuscular Junction
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SLIDE
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Steps of Muscle Contraction and Relaxation
A. Excitation B. Excitation-contraction coupling C. Contraction D.Relaxation |
A. Excitation – nerve action potentials lead to action potentials in muscle cell
B. Excitation-contraction coupling – action potentials in the muscle activate microfilaments C. Contraction – shortening of muscle fiber D. Relaxation – return to resting length |
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Excitation
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SLIDE
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Excitation-Contraction Coupling
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SLIDE
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Contraction
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Slide
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Relaxation
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Slide
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Muscle Length vs. Tension
A. Amount of tension generated depends B. A muscle that is already contracted can't contract any further because? C. A muscle that is too stretched out can't |
A. Amount of tension generated depends on length of muscle before it was stimulated
B. A muscle that is already contracted can’t contract much further because the thick filaments are close to the Z discs C. A muscle that is too stretched out can’t contract strongly because there is not much overlap of thick and thin filaments (i.e. not many places for actin-myosin cross-bridges to form) |
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Muscle Twitches and Work
A. A single nerve signal C. In order for work to be done? |
A. A single nerve signal can cause a single muscle twitch
B. This is not enough to do useful work C. In order for work to be done, nerve impulses must come at fast frequency to a number of muscle fiber cells |
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Recruitment
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SLIDE
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Tetanus
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SLIDE
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Energy Supply for Muscle Work
A. Immediate B. Short-term C. Long-term |
A. Immediate = myoglobin and phosphagens (myokinase and creatine kinase); used up in about 6 seconds of sprinting
B. Short-term = glycogen and lactic acid; good for 30-40 seconds of maximum activity C. Long-term = aerobic respiration; respiratory and cv systems must deliver enough oxygen to support aerobic respiration |
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Fatigue and Endurance
A. Fatigue is due B. Endurance is 3 things that affects endurance |
A. Fatigue due to glycogen depletion, lactic acid accumulation, etc
B. Endurance is ability to maintain high intensity exercise for more than 5 minutes 1) Age – rate of oxygen uptake peaks in young adulthood, then starts to decline 2) Training – increases oxygen uptake efficiency, ability to store glycogen 3) Nutrient availability – carbohydrate loading to maximize glycogen storage |
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Cardiac Muscle
A. type of cells B. Linked together by C. Pacemaker D. Cardiac muscle relies on? |
A. Striated cells but cells are shorter and thicker than skeletal muscle
B. Linked together by intercalated discs – allows rapid transmission of action potential from cell to cell C. Pacemaker cells of heart generate contraction (self-regulating) D. Cardiac muscle relies on aerobic respiration; it is very resistant to fatigue but susceptible to oxygen deprivation |
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Smooth Muscle
A. No... B. Nerve supply C. Contracts D. maintains tensions with? |
A. No striations or sarcomeres; no t-tubules
B. Nerve supply, if present, is autonomic (neurotransmitter released is acetylcholine or norepinephrine) C. Other smooth muscle contracts due to hormones, oxygen, etc. D. Maintains tension with less use of energy |
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Overview of Cell Communications
Mechanisms A. Gap juctions B. Neurotransmitters C. Paracrine hormones D. Hormones |
Necessary for integration of cell activities
A. Gap junctions – pores in cell membrane allow signaling chemicals to move from cell to cell B. Neurotransmitters - released from neurons to travel across gap to 2nd cell C. Paracrine hormones - secreted into tissue fluids to affect nearby cells D. Hormones (strict definition) - chemical messengers that travel in the bloodstream |
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Endocrine System Components
A. Hormone B. Target cells C. Endocrine glands D. Endocrine system |
A. Hormone - chemical messenger secreted into bloodstream, stimulates response in another tissue or organ
B. Target cells - have receptors for hormone C. Endocrine glands - produce hormones D. Endocrine system 1) endocrine organs (thyroid, pineal, etc) 2) hormone producing cells in organs (brain, heart and small intestine) |
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Endocrine Organs
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SLIDE
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Endocrine vs. Exocrine Glands
A. Exocrine glands B. Endocrine glands |
A. Exocrine glands
1) Ducts carry secretion to a surface or organ cavity (sweat, digestive enzymes, etc.) 2) Extracellular effects (food digestion) B. Endocrine glands 1) Release hormones into extracellular fluid, dense capillary networks pick up hormone which are distributed throughout body 2) Intracellular effects; alter target cell metabolism |
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Nervous vs. Endocrine Systems
A. Communication B. Speed and persistence of response C. Adaptation to long-term stimuli D. Area of effect |
A. Communication
Nervous - both electrical and chemical signals Endocrine - only chemical signals B. Speed and persistence of response Nervous - reacts quickly (1 - 10 msec), stops quickly Endocrine - reacts slowly (hormone release in seconds or days), effect may continue for weeks C. Adaptation to long-term stimuli Nervous - response declines (adapts quickly) Endocrine - response persists D. Area of effect Nervous - targeted and specific (one organ); only the cell(s) directly innervated Endocrine - general, widespread effects (many organs) |
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Nervous and Endocrine Systems
A. NE B. Neuroendocrine cells are C. Systems regulate each other |
A. Several chemicals function as both hormones and neurotransmitters – notably NE
B. Neuroendocrine cells are neurons that release hormones instead of neurotransmitters – oxytocin and catecholamines C. Systems regulate each other 1) Neurons trigger hormone secretion 2) Hormones stimulate or inhibit neurons |
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The HPA Axis
A. provides B. Controls C. Circulate D. All parts of the system are? |
A. The hypothalamus-pituitary-adrenal (HPA) axis provides an excellent example of how endocrine function may be controlled
B. The hypothalamus controls pituitary function either by direct neural input (neurohypopysis) or by release of releasing/inhibiting factors (adenohypophysis) C. Hormones from the pituitary circulate and affect adrenal function D. All parts of the system are affected by hormonal modulation (feedback) and neural modulation (sensory input) |
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Posterior Pituitary
A. Hormones are made in B. Action potential travel C. Hormone release is controlled by |
A. Hormones are made in cells whose cell bodies lie within the hypothalamus
B. Action potential travel to the axon terminals, which are in the posterior pituitary, and hormone is released into the bloodstream C. Hormone release is controlled by sensory input from a number of neurons |
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Hypothalamo-Hypophyseal Portal System
SLIDE A. Hormones travel B. Hormones secreted |
A. Hormones travel in portal system from hypothalamus to anterior pituitary
B. Hormones secreted by anterior pituitary |
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Anterior Pituitary Hormones
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SLIDE
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Pituitary Hormones
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SLIDE
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Control of Pituitary: Feedback from Target Organs
SLIDE |
A. Negative feedback
increase target organ hormone levels inhibits release of tropic hormones B. Positive feedback stretching of uterus increase OT release, causes more stretching of uterus, until delivery |
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Pineal Gland
A. Peak secretion B. Produces C. Regulate D. Melatonin/ PMS |
A. Peak secretion ages 1-5; secretion declines with age
B. Produces serotonin by day, converts it to melatonin at night C. May regulate timing of puberty in humans D. Melatonin increase in SAD + PMS; increase by phototherapy 1) depression, sleepiness, irritability and carbohydrate craving |
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Thymus
A. Location B. Involution C. Secretes |
A. Location: mediastinum, superior to heart
B. Involution (shrinkage) after puberty C. Secretes hormones that regulate development and later activation of T-lymphocytes 1) thymopoietin and thymosins |
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Thyroid Gland Anatomy
SLIDE |
Largest endocrine gland; high rate of blood flow
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Thyroid Gland
A. Thyroid follicles B. Thyroid hormone C. C cells |
A. Thyroid follicles – lined with simple cuboidal epithelial cells that produce T3 and T4 (thyroid hormone)
B. Thyroid hormone 1) body’s metabolic rate and O2 consumption 2) Calorigenic effect - heat production 3) heart rate and contraction strength 4) respiratory rate 5) Stimulates appetite and breakdown CHO, lipids and proteins C. C (calcitonin or parafollicular) cells – between follicles 1) Produce calcitonin that blood Ca2+ , promotes Ca2+ deposition and bone formation especially in children |
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Parathyroid Glands
A. PTH release |
A. PTH release
blood Ca2+ levels promotes synthesis of calcitriol absorption of Ca2+ decrease excretion of Ca2+ bone resorption |
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Adrenal Gland
A. Adrenal medulla B. Adrenal cortex |
A. Adrenal medulla NE and E
1) Modified neurons release NE and E as hormones, leading to a stress response (↑HR and BP, ↑glucose levels of blood, ↑pulmonary air flow, ↑muscle blood flow) B. Adrenal cortex corticosteroids 1) Mineralocorticoids – aldosterone (promotes sodium retintion) 2) Glucocorticoids – cortisol (stimulate fat and protein catabolism; anti-inflammatory) 3) Sex steroid – estrogens and DHEA (converted to testosterone) |
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Pancreas
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SLIDE
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Pancreatic Hormones
A. Inlets B. Insulin C. Glucagon D. Somatostatin |
A. Islets produce hormones; 98% of organ is exocrine and produces digestive enzymes
B. Insulin (from cells) 1) Secreted after meal to stimulate cells to take up glucose and amino acids 2) Stimulates glycogen, fat and protein synthesis antagonizes glucagon C. Glucagon (from α cells) 1) Secreted when blood glucose is low to stimulate cells to release glucose 2) Stimulates glycogen, fat, and protein breakdown D. Somatostatin (from δ cells) 1) Secreted after a meal 2) Paracrine action inhibits insulin and glucagon release |
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Endocrine Functions of Other Organs
A. Heart B. Liver C. Kidneys D. Stomach and small intestine E. Placenta |
A. Heart – atrial natriuretic peptide (ANP) – increases sodium and water loss by kidney to decrease blood volume and blood pressure
B. Liver 1) Erythropoietin (stimulates bone marrow) 2) Angiotensinogen (a prohormone) C. Kidneys 1) Erythropoietin 2) Converts hormones angiotensis and caliciol D. Stomach and small intestines make 10 enteric hormones E. Placenta – secretes estrogen, progesterone, and other hormones to support pregnancy |
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Hormone Chemistry
A. Steroids B. Pepties and glycoproteins C. Monoamines |
A. Steroids
1) derived from cholesterol 2) sex steroids, corticosteroids B. Peptides and glycoproteins 1) OT, ADH; all releasing and inhibiting hormones of hypothalamus; most of anterior pituitary hormones C. Monoamines (biogenic amines) 1) derived from amino acids catecholamines (norepinephrine, epinephrine, dopamine) and thyroid hormones |
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Hormone Transport
A. Monoamines and peptides B. Steroids and thyroid C. Transport proteins |
A. Monoamines and peptides are hydrophilic
1) mix easily with blood plasma B. Steroids and thyroid hormone are hydrophobic 1) must bind to transport proteins for transport 2) bound hormone - attached to transport protein, I) prolongs half-life to weeks II) protects from enzymes and kidney filtration 3) unbound hormone leaves capillary to reach target cell (half-life a few minutes) C. Transport proteins in blood plasma 1) albumin, thyretin and TGB (thyroxine binding globulin) bind to thyroid hormone 2) steroid hormones bind to globulins (transcortin) 3) aldosterone - no transport protein, 20 min. half-life |
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A. Located
B. Usually C. Exhibit |
A. Located on plasma membrane, mitochondria, other organelles, or in nucleus
B. Usually thousands for given hormone 1) hormone binding turns metabolic pathways on or off C. Exhibit specificity and saturation |
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Hormone Mode of Action
SLIDE A. Hydrophobic hormones B. Hydrophilic hormones |
A. Hydrophobic hormones
1) penetrate plasma membrane – enter nucleus B. Hydrophilic hormones 2) must bind to cell-surface receptors |
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Thyroid Hormone Effects
A. TH B. Na+-K+ ATPase |
A) TH binds to receptors on
1) mitochondria rate of aerobic respiration 2) ribosomes and chromatin protein synthesis B) Na+-K+ ATPase produced 1) generates heat |
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Hydrophilic Hormones: Mode of Action cAMP as Second Messenger
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1) Hormone binding activates G protein
2) Activates adenylate cyclase 3) Produces cAMP 4) Activates kinases 5) Activates enzymes 6) Metabolic reactions: -synthesis -secretion -change membrane potentials |
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Hydrophilic Hormones: Mode of Action Other 2nd and 3rd Messengers
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Hormones may use different second messengers in different tissues.
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Hormone Clearance
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A. Hormone signals must be turned off
B. Take up and degraded by liver and kidney C. Excreted in bile or urine D. Metabolic clearance rate (MCR) E. Half-life - time required to clear 50% of hormone |
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Paracrine Secretions
A. Chemical messengers that B. Examples and their function |
A. Chemical messengers that diffuse short distances and stimulate nearby cells
1) unlike neurotransmitters not produced in neurons 2) unlike hormones not transported in blood B. Examples and their functions 1) histamine from mast cells in connective tissue causes relaxation of blood vessel smooth muscle 2) nitric oxide from endothelium of blood vessels, causes vasodilation 3) somatostatin from gamma cells, inhibits secretion of alpha and beta cells 4) catecholamines diffuse from adrenal medulla to cortex |
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Eicosanoids: a Paracrine Secretion
A. Leukotrienes B. Prostacyclin C. Thromboxanes D. Prostaglandins |
A) Leukotrienes
1) converted from arachidonic acid (by lipoxygenase) 2) mediates allergic and inflammatory reactions B) Prostacyclin (by cyclooxygenase) 1) inhibits blood clotting and vasoconstriction C) Thromboxanes (by cyclooxygenase) 1) produced by blood platelets after injury; override prostacyclin, stimulates vasoconstriction and clotting D) Prostaglandins (by cyclooxygenase): diverse; includes 1) PGE: relaxes smooth muscle in bladder, intestines, bronchioles, uterus and stimulates contraction of blood vessels 2) PGF: opposite effects |
