Transcript Nerve Conduction

SKIN
Hair shaft
Receptor for
touch
pore
Epidermis
Sebaceous
gland
Dermis
Arrector Pili
muscle
Subcutaneous
Hair
follicle
Receptor for
pressure
Adipose tissue
Sweat gland
Epidermis
-- bottom or basal layer continually reproduces new
cells (Mitosis)
-- top layer hardens because of Keratin, a fibrous
waterproof protein
-- thickest on palms of hands & soles of feet
-- contains Melanocytes, that produce Melanin
-- a pigment responsible for skin color
Dermis
-- contains elastic & collagen fibers
-- contains nerve fibers & blood vessels
Epidermis + Dermis = Cutaneous Membrane (Skin)
FUNCTIONS OF THE SKIN
1. Protection
-- considered our First Line of Defense
against physical trauma, bacterial
invasion, & fluid loss
2. Synthesis of Vitamin D
-- contains a molecule that converts
to Vit. D when exposed to
Ultraviolet light
3. Sensory Reception and Communication
-- helps us feel pressure, pain, hot & cold
4. Regulation of Body Temperature
-- blood vessels constrict, & sweat
gland become inactive
Functions of the Skeletal System
1. Provides framework & gives us shape
2. Protects vital organs
3. Serves as levers for muscles
& permits flexible movement
4. Stores minerals
-- 99% of the body’s Calcium
& 88% of the body’s Phosphorus
is stored in the bones
5. Produces all the blood cells from
the red bone marrow
-- found in flat bone & ends of long bones
Cranium
Scapula
Sternum
Vertebrae
Radius
Carpals
Metacarpals
Phalanges
Fibula
Metatarsals
Phalanges
Face
Clavicle
Humerus
Ribs
Ulna
Coxal
Sacrum
Coccyx
Femur
Patella
Tibia
Tarsals
Types of Bones
1. Flat Bones
-- Ex. skull or cranium; ribs;
sternum; hip bones
2. Short Bones -- Cube-shaped
-- Ex. wrists & ankles
3. Irregular Bones
-- Vertebrae & facial bones
4. Long Bones
-- humerus; radius, femur
-- femur is the longest bone in the body
Structure of Long Bones
Epiphysis
Ends of the bone
Articular Cartilage
Epiphyseal disk
(growth plates)
Yellow Marrow
(contains fat)
Diaphysis
shaft
Periosteum
Tough connective tissue
covering bones
Endosteum
Lines marrow cavity
Epiphysis
Compact Bone
Marrow (medullary) cavity
Spongy Bone
(contains yellow marrow)
BONE FORMATION
Begins in the Fetus in about the 3rd month.
-- Cartilage begins to be replaced with bone by the
process of Ossification
-- Osteoblasts (Bone Building Cells) become active
& start producing Collagen.
-- With the help of enzymes, Calcium salts are deposited
between the osteoblasts.
-- When this material hardens, the cells can no longer
reproduce and are now called Osteocytes
-- Closure of the epiphyseal discs occurs between the 16 & 25.
-- Osteoclasts -- break down bone
-- Bone is continually being broken down and built back
up again.
TERMS
LIGAMENT -- connects bone to bone
TENDON -- connects muscle to bone
JOINTS -- union of two or more bones
-- articulation
-- Fixed
-- Ex. Skull
-- Limited -- Ex. vertebrae
-- Moveable --Ex. shoulder, knee, hip
Differences
Male Pelvis
Male
-- smaller in size
-- bones are denser
-- Pelvic cavity more
funnel shaped
Female
Female Pelvis
-- greater flaring
of the iliac bone
-- pelvis is wider
-- pelvic cavity is
shallow
-- bones are thinner
& lighter
JOINTS
Function of Joints
1. Provides for expansion & molding in infants.
2. Allows for flexibility and movement.
Types of Joints
-- joints determine the amount of movement allowed
1. Synarthrosis -- immovable
2. Amphiarthrosis -- slightly moveable
3. Diarthrosis
-- freely moveable
-- also called a Synovial joint
-- contains Synovial Fluid that acts as a
cushion & allows for ease of movement
-- Fluid is thick & colorless
Gliding
-- allows for sliding or twisting
-- ankles & wrists
Ball &
Socket
Hinge
Pivot
Hinge
-- allows for movement in one
direction (back & forth)
-- elbows, knees, & fingers
Pivot
-- allows for rotation
-- cervical vertebrae &
proximal ends of ulna & radius
Gliding
Condyloid
Saddle
-- movement in 2 direction, but no rotation
-- wrists & forearms, metacarpals & phalanges, & jaw
Saddle
-- allows for more movement (hand & thumb)
Ball & Socket
-- movement in many directions (hips & shoulders
MUSCLES
Types of Muscles
1. Skeletal
-- voluntary
-- striated
-- make up the bulk of the human body
2. Visceral
-- involuntary
-- smooth
-- stomach, intestines, blood vessels
3. Cardiac
-- involuntary
-- only found in the heart
FASCIA
-- fibrous connective tissue that covers muscles
-- it extends out to become the Tendon
-- the fascia layer closest to the muscle is called
Epimysium
Muscle fibers (cells) are
arranged in bundles & work
in groups
-- Perimysium divides the
muscles into bundles
-- Endomysium is the fascia
layer that covers each fiber
Skeletal Muscle Function
1. Muscles & bones work as a system of levers
2. Muscles have two attachment sites
-- Origin
-- less moveable part
-- Insertion
-- put muscle into action
3. Many skeletal muscles function in pairs
-- Prime Mover
-- Synergists
-- muscles that help
the Prime Mover
-- Antagonist
4. Muscles are in a partial state of contraction
even when they are not in use
-- this is called TONE
5. Muscle cells can be excited by:
-- Mechanical means (you choose to move it)
-- Chemical means (use of Neurotransmitters)
-- Electrical means
(nerve impulses)
Movement of Sodium (Na+)
& Potassium (K+) in and
out of the cells
Acetylcholine is the
neurotransmitter involved
here
Nerve Conduction
Na+
Na+
Na+ Na+
Na+
+
+
+
-
-
K+ K+
+
-
K+
+
-
-
+
K+ K
Na+
K+
K+
Na+
Neuron Negatively charged / Resting Potential
Neurotransmitter is released by axon
of previous Neuron / Action Potential
Na+
K+
+ +
+
+
Na+
Na+
+ +
+
+
+
- -+ - + - -+
Na Na Na
+
Na+ Na+ K+Na+
Na+
K+ K+
Acetylcholine
K+
K+
K+
Na+
K+ K+
The Neurotransmitter causes cell membrane of
receiving Neuron becomes permeable to Sodium (Na+)
Na+
K+
K+
Na+
K+
+ +
+
+
+
Na+ Na+ K+Na+
Na+
K+
K+
K+
Na+ moves into cell until saturated
& Potassium (K+) moves out
Neuron becomes Positively charged / Depolarization
Na+
K+
+ +
Acetylcholinesterase
+
+
+
Na+ Na+ K+Na+
Na+
K+
K+
Enzyme is released by receiving Neuron
Cell membrane reverts back to
being impermeable to Na+
Sodium - Potassium Pump in cell
membrane causes Na+ to move out
and K+ to move back into cell
Na+
Na
Na+ Na+ Na+
++
+
-
-
+
-
+
-
+
-
K+ K+ K+ K+ K+
Na+
Na+
K+
K+
Neuron is now Negatively-charged
once again / Repolarization
6. Muscles get their energy from ATP
(Adenosine Triphosphate) released by oxidation
-- oxidation is the burning of food (Glucose)
-- Muscles store Oxygen as Myoglobin
& glucose as glycogen
As long as muscles have enough oxygen & nutrients
the exercise is called AEROBIC (Endurance-type)
-- if no oxygen is available, some ATP can be
supplied by Anaerobic Respiration
-- a waste product of this is Lactic Acid,
which in elevated levels will eventually
interfere with muscle contraction
7. Contraction of muscle fibers produce most of the
heat required to maintain body temperature
8. Special proteins called ACTIN & MYOSIN
allow muscle fibers to contract
-- Calcium is need for the Actin
& Myosin to slide over
each other & form a
bridge
-- ATP is need for
detachment
Calcium ions
Actin
-- A Ca+ pump pulls
Ca+ back into
cell wall when no
longer needed
Relaxed muscle
Myosin
Contracted
muscle
TERMS
Excitability -- capacity to respond to a stimuli
Contractility -- capacity to undergo shortening
& to change shape
Elasticity -- the innate tension that causes the
muscle to assume a desired shape
regardless of how it is stretched
Isotonic -- tension remains the same but muscle
shortens (requires movement)
Isometric -- no change in length, but great increase
in tension (no movement)
TYPES OF MOVEMENTS
Elevation & Depression
-- shrug shoulders
Abduction
(away from the
midline)
Adduction
(toward the midline)
Circular movements
-- shoulders & hips
Dorsiflexion
-- pointing toes toward
the head
Plantar Flexion
-- pointing toes downward
Flexion
(decrease in angle)
Extension
(increase in angle)
Supination
-- palm up
Pronation
-- palm down
Inversion
-- turning sole of foot
inward
Eversion
-- turning sole of
foot outward
Temporalis
Frontalis
Orbicularis
Oris
Sternocleidomastoid
Deltoid
Triceps
Brachii
Pectoralis
Biceps
Brachii
Vastus
lateralis
Sartorius
External
Oblique
Rectus
Femoris
Vastus
Medialis
Occipitalis
Trapezius
Latissimus
dorsi
Gluteus
medius
Semitendenosus
Gluteus
maximus
Semimembranosus
Gastrocnemius
Achilles
tendon