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Chapter 19

Chapter 19. Sex Differences and Athleticism: Endocrine, Skeletal, and Muscular Systems. 19.1 The Endocrine System - Hormones. Endocrine System Internal system to regulate bodily functions 3 Parts of Endocrine system Endocrine glands secrete hormones Hormones are chemical signals

emery-kaufman
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Chapter 19

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  1. Chapter 19 Sex Differences and Athleticism: Endocrine, Skeletal, and Muscular Systems

  2. 19.1 The Endocrine System - Hormones Endocrine System • Internal system to regulate bodily functions 3 Parts of Endocrine system • Endocrine glands secrete hormones • Hormones are chemical signals • Target cells with specific receptors for hormones

  3. 19.1 The Endocrine System - Hormones Two main types of hormones • Protein • Steroid – lipid hormone made from cholesterol Two mechanisms by which hormones interact with target cells: • They bind to receptors on the cell’s surface • Protein hormones • They diffuse across the cell membrane • Steroids

  4. 19.1 The Endocrine System Protein Hormones • Proteins cannot cross cell membrane • Bind to receptors on cell membrane • “Signal transduction” pathway of proteins carries signal inside cell • Changes ACTIVITY of EXISTING cell components • Enzymes, ion channels Figure 19.1

  5. 19.1 The Endocrine System Steroid Hormones • Steroids can cross cell membrane • Bind to DNA to regulate gene transcription • Control production of NEW proteins • such as enzymes and ion channels Figure 19.1

  6. 19.1 The Endocrine System - Hormones Steroid Hormone Example • Sex hormones estrogen and testosterone are responsible for male and female anatomical development. (a) Breast tissue can respond to estrogen. Nucleus Noreceptor Testosterone Estrogenreceptor Estrogen Breastcell Proteins involved inbreast development mRNA (b) The larynx responds to testosterone. Nucleus Noreceptor Estrogen Testosteronereceptor Testosterone Larynxcell mRNA Proteins involved inlarynx development Figure 19.2

  7. 19.1 The Endocrine System (a) Some examples of endocrineorgans (b) Endocrine organs involvedin producing sex differences Hypothalamussecretesgonadotropin-releasing hormone (GnRH). Thyroidsecretes calcitonin tolower blood calcium levels. Pituitaryglandresponds to GnRH bysecreting the pituitarygonodatropins—follicle-stimulatinghormone (FSH) and luteinizing hormone(LH). Parathyroidssecreteparathyroid hormoneto raise blood calciumlevels. Thymussecretesthymosin, whichstimulates T cells ofthe immune system. Adrenalglandssecrete adrenaline,testosterone (masculinizing hormone),and estrogen (feminizing hormone). Ovariesrespond to FSH and LH bysecreting estrogen, which regulatesmenstruation, maturation of egg cellsbreast development, pregnancy, and menopause. Pancreassecretes insulinand glucagon to regulateblood glucose levels. Testesrespond to FSH and LH bysecreting testosterone, which aidsin sperm production, increasedmuscle mass, and voice deepening. Endocrine glands = groups of cells or organs that secrete hormones Figure 19.3

  8. 19.1 The Endocrine System Hypothalamus GnRH Bloodflow Pituitarygland FSH LH Stimulatesspermproduction Stimulatestestosteroneproduction Stimulatesegg celldevelopment Stimulatesovulation Hypothalamus • regulates body temperature, affects hunger, thirst, and reproduction • GnRH - Gonadotropin-releasing H. Pituitary • secretes a wide variety of hormones, including • Growth Hormone • FSH – Follicle Stimulating H. • LH – Luteinizing H. Figure 19.4

  9. 19.1 The Endocrine System - Endocrine Glands - Adrenal glands Adrenal Glands • Sit on top kidneys • Secrete: • Adrenaline • Stress hormones – cortisol, corticosterone • Small amounts of sex hormones (testosterone and estrogen)

  10. 19.1 The Endocrine System - Endocrine Glands - Testes Testes • Secrete testosterone • Sperm production • Hair thickness and distribution • Muscle mass • Voice deepening • Sperm production is more efficient at temperatures lower than body temperature • Testes in scrotum outside of body cavity

  11. 19.1 The Endocrine System - Ovaries Ovaries • Secrete estrogen & progesterone • Regulates Menstruation • Maturation of egg cells • Breast development • Pregnancy • Menopause • Production of eggs cells begins in utero

  12. 19.1 The Endocrine System - Endocrine Glands Puberty • Beginning of sperm production in males and egg production in females • Age 8 to 13 years old for females, • Age 9 to 14 years old for males • Differences in athletic performance are due to affects of sex hormones on skeletal and muscle development

  13. 19.1 The Endocrine System PLAY Animation—The Endocrine System

  14. 19.2 The Skeletal System Skeletal system Functions: • Supports the body • Protects internal organs • Aids movement • Stores minerals

  15. 19.2 The Skeletal System - The Human Skeleton • Human skeleton is composed of 206 bones divided into 2 units • Axial skeleton – ribs, spine, skull • Appendicular skeleton – limbs, pelvic and pectoral girdles Figure 19.5

  16. 19.2 The Skeletal System - The Human Skeleton (b) Hinge joint (knee) (a) Ball and socket joint (hip) Pelvic bone Femur Tibia Femur Fibula (c) Pivot joint (neck) Atlas Axis • Joints in the skeleton allow for a variety of movements. Figure 19.6

  17. 19.2 The Skeletal System - Bone Structure and Remodeling Cartilage Spongybone Compactbone Marrow Bloodvessel Bone is a living, dynamic tissue that varies depending on function. • Compact bone: densely packed, forms the hard, outer shell of bones • Spongy bone: loosely packed, porous, honeycomb-like, interior • Marrow – interior of bone, produces blood cells • Bones have blood vessels inside and along their surface Figure 19.7

  18. 19.2 The Skeletal System - Bone Structure Bones act as a reservoir of calcium • they can store excess calcium or release it as needed • Osteoblasts – remove calcium from blood during bone deposition process • Osteoclasts – add calcium to blood by breaking down and reabsorbing bone tissue • Bones are in a continuous process of remodeling

  19. 19.2 The Skeletal SystemEndocrine regulation of Calcium • Parathyroid gland releases parathyroid hormone • stimulates osteoclasts • Releases calcium to blood Figure 19.8

  20. 19.2 The Skeletal SystemEndocrine regulation of Calcium • Thyroid gland releases calcitonin • Stimulates osteoblasts • Removes calcium from blood and deposits it in bone Figure 19.8

  21. 19.2 The Skeletal System - Sex Differences in Bone Structure • Due to timing and length of puberty, on average males have longer limbs than women • On average men are 5.9” taller than women • Longer limbs = more power in lever action of limbs • Women have wider pelvis and lower center of gravity = better balance

  22. 19.2 The Skeletal System Sex Differences in Bone Structure Figure 19.9

  23. 19.3 The Muscular System The Muscular System • 3 types of muscle in human body: • Skeletal • Cardiac • Smooth

  24. 19.3 The Muscular System - Muscle Interactions With Bone • Muscles and tendons interact with bones to cause movement. They usually work in antagonistic pairs. Figure 19.10

  25. 19.3 The Muscular System Muscle Structure and Contraction • Muscles is composed of bundles of muscle fibers arranged in parallel. • Muscle fibers are cells • Inside cells are myofibrils

  26. 19.3 The Muscular System Muscle Structure and Contraction • Myofibrils contain repeating elements: • Sarcomeres – the functional unit of a muscle • Sarcomeres contain interacting actin and myosin ‘filaments’

  27. 19.3 The Muscular System Sarcomere Structure and Contraction • Sarcomeres run from Z-disc to Z-disc • Actin (thin filaments) attach to Z disc on both sides • Myosin (think filaments) overlap with actin

  28. 19.3 The Muscular System Sliding Filament Model Myosin has heads that act as ratchets ATP causes head to move to cocked position Head binds to actin and pulls Shortens sarcomere Figure 19.12

  29. 19.3 The Muscular System PLAY Animation—Contraction of Skeletal Muscle

  30. 19.4 Sex Differences That Influence Athleticism Body Fat Differences • On average women have 10% more body fat than men. • Women begin storing fat on hips, thighs, buttocks and torso at puberty. • Men carry most of their fat on their abdomen. • In women, excessive loss of body fat can lead to cessation of menstrual cycle.

  31. 19.4 Other Sex Differences That Influence Athleticism Cardiovascular Differences • On average, compared to men of similar size, women have: • smaller hearts • less blood volume • Fewer RBC’s per ml blood • smaller lungs • Same amount of aerobic effort puts greater strain on woman’s cardiovascular system

  32. 19.4 Sex Differences That Influence AthleticismGroup Differences and Individual Differences 32 29 Percent body fat 12 Most menand womenfall in thesame range. 3 Men Women • Averages hide the fact that in large groups, there is much variation. • Ranges for males & females overlap a great deal Figure 19.14

  33. 19.4 Sex Differences That Influence Athleticism Summary • Physical activity is important to health regardless of gender • Children who exercise are more likely to do so as adults • Good exercise habits have many benefits • Decreased risk of heart disease, obesity, diabetes, and many cancers • Regular exercise decreases anxiety and depression

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