Transcript Human Anatomy & Physiology

•Introduction
•Structure &
Support
•The Skeletal, Muscular and Integumentary Systems
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"Levels of Organization"
Cell
 Tissue
 Organ
 System
 entire organism

Campbell/Reece
Chapter 40.2
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Body Tissues:
1. Muscle Tissue
 function in movement, etc.
 Ex:
2. Nervous Tissue:
 function in communication and coordination
 Ex:
3. Epithelial Tissue:
 function in secretion/absorption of materials;
 covering of internal/external body surfaces
 Ex:
4. Connective Tissue:
 functions to bind together and support other structures;
forms bone and organ walls
 Ex:
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Humans have Bilateral Symmetry

"cephalization“
 From Latin and Greek origins: cephalicus
and kephalikos respectively, both meaning
"head".
anterior:
 posterior:
 dorsal:
 ventral:

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BODY CAVITIES
Cranial Cavity
 Thoracic Cavity
 Abdominal Cavity

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BONES - The Human Skeletal System
Campbell/Reece
Chapter 49.5
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BONE as a tissue:
strongest and hardest of all
tissues
 living bone continually
grows and changes
 "osteocyte"-bone cell

Formation of bone:
 Most bone begins as soft
tissue (cartilage) and
develops layers of bone
cells
 --->Ossification <--7
BONE STRUCTURE:
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Periosteum- tough, fibrous outer
membrane, outermost covering of
bone
Compact Bone- hard tube of bone
tissue
Spongy Bone- softer, porous bone
found at ends of bone (knobs)
Haversian Canals - network of
channels through bone; contain
blood vessels (makes bone porous)
Red Marrow - found inside long
bones - produces, contains immature
red blood cells
Yellow Marrow - found in some
bones; consists of fatty materials; will
produce blood cells
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Cartilage
Tough, flexible tissue
 structural: nose, ears
 protection: ends of bones (joints)
 1. cushions bones (shock absorbency)
 2. prevents bones from rubbing against each
other
 3. provides smooth gliding surface
connects ribs to sternum
 cartilage disks between vertebrae of
backbone

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The SKELETONtext reference pg. 909 Fig. 46-3

2 regions:
 AXIAL
 APPENDICULAR

Girdles: pectoral &
pelvic
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JOINTS

Where two bones meet
Types/motion/locations:
(link)
Fixed joints
Ball & Socket
Hinge
Saddle (ex: base of thumb; for
rotation)
 Gliding (allow bones to slide over
one another; ex foot flexion)

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Tendons: hold muscles to bones

Ligaments: hold adjacent bones
together; in joints
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DISEASES of the bone:
Osteoporosis
 Arthritis

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MUSCLES -The Human Muscular System
text reference: Campbell/Reece Chapter
49.6
 >7,600 muscles in human body
 make up about 40% of the body’s weight

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Types of Muscles
Specialized for contraction
May be:
 voluntary
 involuntary
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"How do muscles know to move?"
Muscles are connected to nerves
("motor unit"); receive impulses from
brain
 Motor neurons (nervous system) control
muscle contraction
 1. axon
 2. synaptic junction
 3. muscle
 4. myofibril

http://highered.mcgrawhill.com/olc/dl/120107/bio_c.swf
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3 TYPES OF MUSCLE TISSUE:
1. Skeletal Muscle (A.K.A. "striated muscle")
 attached to bones (connected to bones with tendons)
 mostly voluntary easily fatiguable
 microscopic analysis: striated (banded), with many small nuclei: Skeletal Muscle
2. Smooth Muscle (visceral)
 found in organ walls (often in a circular pattern)
 involuntary; ex. breathing, digestion, blood vessel diameter
 fatigues slowly
 microscopic analysis: flat, thin appearances, spindle-shaped, nucleated at center
 for: stomach (churning) , intestine, diaphragm (raise/lower), vasoconstriction,/ vasodilation
in walls of blood vessels
3. Cardiac Muscle
 found in the heart
 involuntary
 infatiguable
 microscopic analysis: slightly striated and swirled, with few visible nuclei
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Action of Muscles
always work in "opposing pairs",
"antagonistic" action (ex.biceps, triceps)
 contract and relax (muscles do not
expand-stretch appreciably)

Animation
http://www.yteach.co.uk/page.ph
p/resources/view_all?id=connect
ive_tissue_creatine_phosphate_
free_fatty_acids_glycogen_myo
globin_synapse_muscle_relaxati
on_extensor_flexor_relaxed_mu
scle_contracted_muscle_tropom
yosin_troponin_t_page_17&from
=search
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Composition of Muscle:
Muscle cells make up muscle fibers
(myofibrils) which form bundles...like
cables
 Bundles of these muscle fibers, often
hundreds of thousands, are held together
by connective tissue (sarcolema)

Myofibrils are stringy, made of two types
of protein: Actin (thin) and Myosin
(thick)
 A sarcomere is the basic unit of a
muscle's cross-striated
myofibril. Sarcomeres are multi-protein
complexes composed of actin and
myosin filaments.
 The sarcomere is the basic contractile
unit of a muscle (see Fig 46-12 pp. 918)
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When the muscle is stimulated, the thin (actin) filaments slide
past the thick (myosin) filaments.
Since the thin filaments are anchored (at the z-line), this
causes the sarcomere to shorten (contract)
 1) Actin - composed of many globular actin molecules assembled in a
chain. Each filament is two chains wrapped around each other
 2) Myosin- composed of bundles of myosin molecules, composed of 2
long protein chains (1,800 Amino Acids), with a globular "head" at one
end

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"Heads" catch in actin fibers, forming temporary "cross
bridges" contraction.
animation of sarcomere shortening in action
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Initiation of Contraction : The Neuromuscular Junction
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Before a muscle can contract, it must be
stimulated by a nerve impulse. These
electrochemical signals travel across a
junction (synapse) via acetylcholine - causes
Ca2+ ion release = contraction
"The Motor Unit" - the axon of a single motor
neuron and all of the muscle fibers that it
enervates
"All or Nothing Response"
(Threshold Stimulus)
animation of neuromuscular junction at work
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Regulation of Muscle Contraction

The contraction of sarcomeres is
dependent upon ATP (energy)
tropomysin: regulatory protein that blocks
myosin-actin attachment while muscle is at
rest
 When Ca2+ attaches to the troponin
complex, it unblocks these binding sites,
allowing the thick/thin filaments to bind,
attach and cause contraction.
 ATP (energy) is expended

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INTEGUMENT
text reference:Ch 46-4
The outer body covering; includes skin,
hair, nails
Functions of Skin:
 1st line of defense (microorganisms,
disease)
 helps to retain body fluids
 temperature regulation
 elimination of waste (sweat)
 warmth

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Layers:
outermost: Epidermis (dead epithelial
cells)
 underneath: Dermis (contains nerves,
blood vessels, lymph vessels)
 under dermis = fat layer (insulation)
 muscle layer

Glands:
 sweat (cooling)
 sebaceous (oil)
Blood vessels: capillaries (dilate to bring
blood to surface to release body heat)

Hair (follicles): for warmth

Nerves: there are receptors for
pressure, touch, pain, and temperature
in the skin. for explanation, try this
link.
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Keratin: is an extremely strong protein which is a major component in skin, hair, nails,
hooves, horns, and teeth.
○ The amino acids which combine to form keratin have several unique properties,
and depending on the levels of the various amino acids, keratin can be inflexible
and hard, like hooves, or soft, as is the case with skin.
○ Most of the keratin that people interact with is actually dead; hair, skin, and nails
are all formed from dead cells which the body sheds as new cells push up from
underneath.
Melanin: Also called pigment, melanin is a substance that gives the skin and hair its
natural color.
○ It also gives color to the iris of the eye, feathers, and scales.
○ In humans, those with darker skin have higher amounts of melanin. By contrast,
those with less pigment have lighter or more fair skin coloring.
○ Melanin, sometimes referred to as a chemical, is formed as part of the process of
metabolizing an amino acid called tyrosine. In the skin, melanin is formed by cells
called melanocytes.
○ more melanin is produced as a response to (and as a protection from ) UV light.

How Stuff Works: self-tanning products?
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