Download Chapter 19: Endocrine, Skeletal, and Muscular Systems

Chapter 19
Sex Differences and Athleticism:
Endocrine, Skeletal, and Muscular Systems
Copyright © 2010 Pearson Education, Inc.
19.1 The Endocrine System - Hormones
Endocrine System
 Internal system to regulate bodily functions
3 Parts of Endocrine system
1. Endocrine glands secrete hormones
2. Hormones are chemical signals
3. Target cells with specific receptors for
hormones
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19.1 The Endocrine System - Hormones
Two main types of hormones
1. Protein
2. 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
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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
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Figure 19.1
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
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Figure 19.1
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
Testosterone
Estrogen
No
receptor
Estrogen
receptor
Proteins involved in
breast development
mRNA
Breast
cell
(b) The larynx responds to testosterone.
Nucleus
Estrogen
Testosterone
Proteins involved in
larynx development
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No
receptor
Testosterone
receptor
mRNA
Larynx
cell
Figure 19.2
19.1 The Endocrine System
Endocrine glands = groups of cells or organs
that secrete hormones
(a) Some examples of endocrine
organs
(b) Endocrine organs involved
in producing sex differences
Thyroid secretes calcitonin to
lower blood calcium levels.
Hypothalamus secretes
gonadotropin-releasing hormone (GnRH).
Parathyroids secrete
parathyroid hormone
to raise blood calcium
levels.
Pituitary gland responds to GnRH by
secreting the pituitary
gonodatropins—follicle-stimulating
hormone (FSH) and luteinizing hormone
(LH).
Thymus secretes
thymosin, which
stimulates T cells of
the immune system.
Adrenal glands secrete adrenaline,
testosterone (masculinizing hormone),
and estrogen (feminizing hormone).
Pancreas secretes insulin
and glucagon to regulate
blood glucose levels.
Ovaries respond to FSH and LH by
secreting estrogen, which regulates
menstruation, maturation of egg cells
breast development, pregnancy, and
menopause.
Testes respond to FSH and LH by
secreting testosterone, which aids
in sperm production, increased
muscle mass, and voice deepening.
Copyright © 2010 Pearson Education, Inc.
Figure 19.3
19.1 The Endocrine System
Hypothalamus
 regulates body temperature,
affects hunger, thirst, and
reproduction
 GnRH - Gonadotropin-releasing H.
Hypothalamus
GnRH
Blood
flow
Pituitary
gland
Pituitary
 secretes a wide variety of
hormones, including
 Growth Hormone
 FSH – Follicle Stimulating H.
 LH – Luteinizing H.
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FSH
LH
Stimulates
sperm
production
Stimulates
testosterone
production
Stimulates
egg cell
development
Stimulates
ovulation
Figure 19.4
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)
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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
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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
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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
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19.1 The Endocrine System
PLAY
Animation—The Endocrine System
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19.2 The Skeletal System
Skeletal system
Functions:




Supports the body
Protects internal organs
Aids movement
Stores minerals
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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
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Figure 19.5
19.2 The Skeletal System - The Human
Skeleton
 Joints in the skeleton allow for a variety of
movements.
(a) Ball and socket joint (hip)
(b) Hinge joint (knee)
Pelvic
bone
Femur
Tibia
Femur
Fibula
(c) Pivot joint (neck)
Atlas
Axis
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Figure 19.6
19.2 The Skeletal System - Bone Structure
and Remodeling
Cartilage
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
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Spongy
bone
Compact
bone
Marrow
Blood
vessel
Figure 19.7
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
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19.2 The Skeletal System
Endocrine regulation of Calcium
 Parathyroid gland
releases parathyroid
hormone
 stimulates osteoclasts
 Releases calcium to
blood
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Figure 19.8
19.2 The Skeletal System
Endocrine regulation of Calcium
 Thyroid gland releases
calcitonin
 Stimulates osteoblasts
 Removes calcium from
blood and deposits it in
bone
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Figure 19.8
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
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19.2 The Skeletal System
Sex Differences in Bone Structure
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Figure 19.9
19.3 The Muscular System
The Muscular System
 3 types of muscle in human body:
1. Skeletal
2. Cardiac
3. Smooth
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19.3 The Muscular System - Muscle
Interactions With Bone
 Muscles and tendons interact with bones
to cause movement. They usually work in
antagonistic pairs.
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Figure 19.10
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
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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’
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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
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19.3 The Muscular System
Sliding Filament
Model
1. Myosin has
heads that act
as ratchets
2. ATP causes
head to move to
cocked position
3. Head binds to
actin and pulls
4. Shortens
sarcomere
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Figure 19.12
19.3 The Muscular System
PLAY
Animation—Contraction of Skeletal Muscle
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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.
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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
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19.4 Sex Differences That Influence Athleticism
Group Differences and Individual Differences
32
29
Percent body fat
 Averages hide the fact that
in large groups, there is
much variation.
 Ranges for males &
females overlap a great
deal
12
3
Men
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Most men
and women
fall in the
same range.
Women
Figure 19.14
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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