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Lecture Outline – Ch. 46: Endocrine System I. Hormone overview II. Hypothalamus & Pituitary III. Thyroid IV. Parathyroid V. Pancreas VI. Ovaries & VII. Adrenals Testes Hormones in Animals Hormones influence growth, development, mood… Hormones in Animals Types of Glands: 1) Exocrine Glands: • Release substances outside the body via ducts • Sweat glands • Salivary glands • Mammary glands 2) Endocrine Glands: • Release substances within the body via bloodstream • Ductless Hormones in Animals Hypothalamus Pineal gland Parathyroid glands (on posterior surface of thyroid gland) Pituitary gland Heart Thyroid gland Kidneys Thymus gland Digestive tract Adrenal glands (one at each kidney) Pancreas islet cells Gonads testis ovary Hormones in Animals Hormones released in response to stimuli Travel through the circulatory system to reach target cells A cell is affected only if it has receptors specific to that hormone Most hormones are controlled by negative feedback, which inhibits further release In a few cases, positive feedback is used to amplify hormone levels Hormones in Animals General Classes of Hormones: Hypothalamus & Pituitary Hypothalamus: • Region of brain • Collection of neurosecretory cells • Make and store peptide hormones • Secretes to anterior pituitary via portal system Hypothalamus & Pituitary Pituitary Gland: hypothalamus • Pea-sized gland; hangs from hypothalamus • Master regulation/ coordination center • Controlled by hypothalamus: • Release hormones • Inhibit hormones pituitary (anterior lobe) pituitary (posterior lobe) Pituitary Anterior Pituitary (adenohypophysis): • True gland • Releases hormones that affect other glands • • • • Follicle-stimulating Hormone (FSH) - egg / sperm production Luteinizing Hormone (LH) - sex hormone secretion Thyroid-stimulating Hormone (TSH) - hormones from thyroid Adrenocorticotropic Hormone (ACTH) - hormones from adrenal cortex Indirect (stimulate other glands) Direct (stimulate tissues) • Prolactin - mammary gland development • Melanocyte-stimulating Hormone (MSH) - synthesis of melanin (skin pigment) • Growth Hormone (GH) - growth of body cells Pituitary Goiters are caused by a lack of iodine in the diet Pituitary “Tom Thumb” (Charles Stratton) Robert Wadlow 8’11” Pituitary Posterior Pituitary (Neurohypophysis): • Extension of cells in hypothalamus • Releases two hormones hypothalamus • Contains neurosecretory cells with bodies in hypothalamus • Antidiuretic Hormone (ADH) • water conservation (kidneys) • Oxytocin • Contraction of uterus muscles • “Milk letdown” reflex • Maternal behaviors pituitary (posterior lobe) Thyroid Gland Thyroid: • Wraps around the front of the larynx in the neck • Regulates metabolism & growth • Controlled by TSH from ant. pit. (Thyroid-Stimulating Hormone) • Secretes Thyroxine (T4 - Amino Acid Hormone): • Iodine required for T4 production larynx thyroid gland esophagus parathyroid glands trachea Parathyroid Gland Parathyroid: • Imbedded in thyroid gland • Regulates blood calcium levels • Secretes Parathyroid hormone (PTH) larynx low blood calcium normal blood calcium release PTH calcium release from bone thyroid gland esophagus parathyroid glands trachea Pancreas Pancreas: • Both exocrine and endocrine: Exocrine = Digestive enzymes (small intestine) Endocrine = Hormones regulating blood sugar Insulin Reduces blood sugar (cells uptake glucose) Glucagon Increases blood sugar (cells release glucose) Type I Diabetes: lack β cells Type II Diabetes: low #s insulin receptors Ovaries & Testes Sex Organs: 1) Ovaries (Female): • Estrogen / Progesterone (steroid hormones) 2) Testes (Male): • Testosterone (steroid hormone) • Controlled by FSH and LH from ant. pit. Follicle-stimulating Hormone Luteinizing Hormone • Functions: • Early development (brain development) • Puberty • Menstrual cycle; pregnancy Adrenal Glands 1) Adrenal Medulla (center of gland) • Epinephrine (Adrenaline)/Norepinephrine (Amino acid hormones): • Prepare for “fight or flight” • Controlled by nervous system adrenal gland Adrenal medulla secretes epinephrine and norepinephrine. kidney Adrenal Glands 2) Adrenal Cortex (outside of gland) • Glucocorticoids (Steroid hormones) • Released in stressful situations • Controlled by ACTH (ant. pit.) • Testosterone adrenal gland Adrenal cortex glucocorticoids, aldosterone, and testosterone. kidney Congenital adrenal hyperplasia (CAH) Other Sources of Hormones 1) Most Cells in Body • Prostaglandins (Fatty Acid Hormones): Ibuprofen • Target = Nearby cells • Function is varied (Inflammation; Uterine contractors) 2) Pineal Gland • Melatonin (Amino Acid Hormone): • Regulate sleep/wake cycle; reproductive cycle (non-humans) 3) Thymus • Thymosin: Stimulates white blood cell production 4) Kidneys • Erythropoietin: Regulates red blood cell production Other Sources of Hormones 5) Adipose Cells: • Leptin: Regulates body fat Leptin tells body how much fat is stored and decreases appetite Link between obesity and leptin sensitivity leptin-deficient mouse normal mouse Hypothalamus produces ADH and oxytocin, regulatory hormones for anterior pituitary A Good Slide to Know Pineal gland melatonin Pituitary gland anterior pituitary: ACTH, TSH, GH, PRL, FSH, LH, and MSH posterior pituitary: releases oxytocin and ADH Parathyroid glands (on posterior surface of thyroid gland) parathyroid hormone Thyroid gland thyroxine, calcitonin Kidneys erythropoietin Thymus gland (atrophies during adulthood) Adrenal glands (one at each kidney) medulla: epinephrine, norepinephrine cortex: glucocorticoids (cortisol), aldosterone, testosterone Pancreas islet cells insulin, glucagon Gonads testes (male): androgens, especially testosterone ovaries (female): estrogens, progesterone testis ovary Self-Check: Pituitary Anterior Posterior Kidney Pancreas Thyroid Gonads Adrenal Medulla Adrenal Cortex Thought Questions: What allows animal movement in response to stimuli? Lecture Outline – Ch.47: Muscular & Skeletal I. Skeletal Muscles A. Structure B. Contraction C. Nerve Input II. Skeletal Systems III. Vertebrate Skeletons A. Support B. Protection C. Movement D. Joints Muscular and skeletal systems Muscles power movement by contracting Bones provide framework for muscles Muscles Muscle Tissue (Muscle = “little mouse”): • Exerts force by contracting Movement due to actin microfilaments and myosin strands Slide past one another, change cell shape Transformation Chemical energy (ATP) Mechanical Energy Muscles Types of Muscle Tissue: Skeletal Muscle Cardiac Muscle Smooth Muscle Striated Striated Not Striated Function Skeletal Movement Pump Blood Move Substances Through Hollow Tubes Control Voluntary Involuntary Involuntary Appearance Skeletal Muscles tendon (to bone) connective tissue nerve and blood vessels bundle of muscle cells Skeletal muscle Muscle fiber (muscle cell) Myofibril (contains thin sand thick filaments) • Humans > 700 unique skeletal muscles • Muscle connected to bones by tendons Skeletal Muscles Cross section of fiber muscle fiber T tubules sarcoplasmic reticulum myofibril - Each muscle cell runs length of muscle plasma membrane - Multinucleate - Made up of myofibrils - Each myofibril surrounded by Contractile cylinders of actin sarcoplasmic reticulum and myosin - Fluid with high calcium levels - T-tubules in plasma membrane relay signals Skeletal Muscles Myofibril sarcomere myofibril Z lines thin filament Myofibrils of “thick” and “thin” filaments. Each filament is made of protein strands. thick filament Filaments arranged in sarcomeres Separated by Z-lines of fibrous protein Skeletal Muscles Thick and thin filaments thin filament myosin heads thick filament (myosin) troponin accessory proteins tropomyosin actin Thick filaments: made mostly of myosin, have small moveable “heads” Thin filaments: primarily actin, have points to which the myosin heads temporarily attach Skeletal Muscles thin filament binding sites myosin head Each actin subunit has binding site for myosin head thick filament Contraction exposes binding sites, allowing filaments to bind to one another ATP ADP Myosin heads then repeatedly bend, pull, release, and reattach (using ATP-energy) Skeletal Muscles Sliding filaments shorten each sarcomere Skeletal Muscles Neuromuscular junctions between axons and fibers All or nothing response: Skeletal muscle excited All sarcomeres respond axon of motor neuron synaptic terminal synaptic vesicles postsynaptic membrane Skeletal Muscles Strength of Muscle Contraction # of Fibers Stimulated Motor Unit: A single motor neuron and all the muscle fibers innervated by it Skeletal Muscles Action potential travels through T-channels and opens Ca++ channels in sarcoplasmic reticulum These ions allow binding of thin and thick fibers Ca++ is pumped back out after action potential ends Unless you’re dead Skeletal Muscles You cannot add muscle fibers You can add more myofibrils bundle of muscle cells muscle Muscle fiber Myofibril (muscle cell) Skeletal Muscles Slow-twitch fibers: Lots of myoglobin (provides O2) and mitochondria. Fast-twitch fibers: Less myoglobin and mitochondria More able to use glycolysis to quickly produce ATP Different people (& muscles) – different ratios of two fibers. 80% slow twitch 50% slow 50% fast 80% fast twitch Skeletal System A supporting framework for the body Skeletal System Hydrostatic skeleton Fluid provides support Muscles contract and move fluid Skeletal System Exoskeleton Hard shells cover outside of body Muscles contract and move frame at joints Skeletal System Endoskeleton Internal framework - least common skeleton type Muscles contract and move frame at joints Vertebrate Skeletons Support body Protect fragile organs Allow movement Produce blood cells Store minerals Transmit vibrations (hearing) Vertebrate Skeletons Bodily Support Axial skeleton- main body axis Appendicular skeleton- appendages and supporting structures Vertebrate Skeletons Protection Skull- brain Vertebral column- nerve cord Ribcage – soft internal organs Vertebrate Skeletons Movement Three skeletal connective tissues Cartilage- tough, but flexible Skeletal development Cushioning joints Ligaments- tough Connect bones at joints Bone- tough and rigid bone cartilage Vertebrate Skeletons Bone = hardened by deposits of calcium phosphate Compact bone (exterior) is dense and strong Spongy bone (interior) is lightweight and porous cartilage chondrocytes osteon spongy bone (contains marrow) collagen matrix compact bone osteocytes capillary central canal Vertebrate Skeletons Blood cell production Red blood cells, white blood cells, platelets Produced by bone marrow Leukemia: cancer of the bone marrow, leads to decreased blood cells Mineral storage Bones store and release calcium and phosphorous to maintain constant concentrations Vertebrate Skeletons Bone cells work together Osteoclasts- bone dissolving cells Dissolve cartilage Osteoblasts- bone forming cells Replace cartilage with bone Osteocytes- mature bone cells Cannot produce more bone, but can remodel it Vertebrate Skeletons Bone remodeling Can alter skeletal shape in response to use Osteoclasts create channels invaded by capillaries and osteoblasts to form new bone Osteoporosis is when activity of osteoclasts outstrips osteoblasts Normal bone section Osteoporosis Vertebrate Skeletons Movement of bones Joints are where two bones meet Lubricated by cartilage Attached by ligaments Muscles are attached to bone on either side of the joint Attached by tendons Ligaments Origin - attachment to still bone Insertion - attachment to moving bone Vertebrate Skeletons Movement Antagonistic muscle pairs pull the bone in opposite directs when they contract Flexor muscle bends the joint Extensor muscle straightens it Vertebrate Skeletons Joints Immovable- joints do not move (skull) Ball & Socket – rotational movement in all directions (hip, shoulder) Hinge – extend or retract an appendage in one direction (knee) Gliding – permit sliding of two surfaces (spine) Combination – utilize more than one of above (jaw) Lecture 11 Summary 1. Overview (Ch. 46) Gland types Classes of hormones 2. Hormones (Ch. 46) Hypothalamus & Pituitary (anterior and posterior) Thyroid & Parathyroid Pancreas Gonads Adrenals 3. Muscles (Ch. 47) Muscle cell types Structure of muscles Contraction/relaxation 4. Skeleton (Ch. 47) Skeleton types Cell types and building bone - Joints and attachments