Human Anatomy - Unit 3

What are the three types of Muscle Tissue

Skeletal, Cardiac, and Smooth

Skeletal Muscle

Striated and voluntary

Cardiac Muscle

Striated and involuntary

Smooth Muscle

Not striated and involuntary

Excitability

The ability to respond to stimulus

Conductivity

The ability to transmit electrical events along the cell membrane.

Contractility

The ability of a muscle to shorten, generally generates tension as it shortens

Extensibility

The ability of a muscle to be stretched beyond it resting length

Elasticity

The ability of a muscle to return to its resting lengthening after shortening or lengthening

Each Skeletal muscle is considered an organ. What are the tissue types that it contains.

-Epithelial Tissue

-Connective Tissue

-Muscle Tissue

-Nervous Tissue

True or False: Muscle usually attaches to bone

True

True or False: Muscles and Muscle cells do not vary in shape or size.

False

What are functions of Skeletal Muscle

-Body Movement

-Maintenance of posture

-protection and support

-Regular elimination of materials

-Heat production

What is Anatomy of skeletal muscle from largest to smallest

1. Whole Muscle

2. Muscle Fascicle: muscle segments

3. Muscle Fiber: cluster or groups of muscle cells

4. Myofibrilis: smaller units composed of myofilaments

5. Myofliamnets: even tinier structures than myofibrilis.

Which structure of Muscle contains thick and thin filaments

Myofilaments

True or False: Muscle tissue have multiple layers of connective tissue within and around them.

True

True or False: Connective tissue layers are composed of only collagen fibers

False: Muscle Tissues are composed of collagen and elastic fibers

What is the function of connective tissue?

-Protection

-sites for blood vessels and nerve distribution

-Attachment to the skeleton

Edomysium

The innermost layer of connective tissue that surrounds individual muscle fibers, providing a network for capillaries and nerve fibers

Perimysium

 connective tissue sheath that surrounds individual muscle fascicles (bundles of muscle fibers), and separates them from other fascicles within the skeletal muscle.

Epimysium

layer of connective tissue that surrounds bundles of muscle fibers (fascicles), separating them and providing support. 

Tendons

Dense, fibrous connective tissue that connects skeletal muscles to bones, transmitting the force of muscle contraction to the bon

Aponeuroses:

Broad, sheet-like tendons that attach muscles to bones or other muscles, providing a wider area for muscle attachment. 

describe the structure and composition of the following microscopic skeletal muscle components: sarcomere, thickfilaments, thin filaments, A-band, I-band, H-zone, Z-disc, and M-line.

a.     A single sacrome run from z disc to z disc

b.     Thin filaments are attached to thin filaments

c.     Along midline are the thick filaments/myasin

d.     Along the centeral of the sarcomere there is the midline

e.     Regions I bands: thin

f.      A bands : always remains constant ,overlap

g.      H zone: thick filament

explain the sliding filament theory of skeletal muscle contraction

During the sliding filament theory thin filaments slide past thick filaments

Z discs move closer together, so sarcomas shorten

Widths of A bands remain constant, but H zones disappear.

I band narrow.

Length of filaments never change whether the muscle is contracted or relaxed: only their relative location.

list the structures that form the neuromuscular junction.

Muscle fibers and motor neurons

explain how muscles contract, beginning with excitation by somatic motor neurons and ending with the intracellular events causing muscle relaxation.

Contraction: We need an impulse central nervous system out, Motor neurons, goes through vesicles and acetoin is relasesed between the synaptic cleft. The impulse goes down to the deep tubules at rest endoplasmic reticulum which then gets us to calcium. Troponin has a binding site for calcium. Tropamysium is able to move and shift to show the bind site. Myosin heads can then attach to actin and pivot, this forms cross bridges. Myosin head then pivots and pulls actin toward the midline. Repeats as long as there is contractions.  

define the term “motor unit” and its role in control of muscle function.

Motor unit is a single motor neuron and the muscle fibers it controls.

It only intervenes on type of fiber/specific muscle fiber

A motor unit contains only some of the muscle fibers in an entire muscle

When a motor unit is stimulated, all muscle fibers within it contracts

identify the characteristics of the three types of skeletal muscle fibers

-slow oxidative fibers (SO) fibers, type I

-fast oxidative (FO) fibers, type IIa

-fast glycolytic (FG) fibers, type IIb

slow oxidative fibers (SO) fibers, type I

-these are small in size, aerobic and fatigue resistant

            -long period of time

            - use atp slowely

            -extensae concentration of capillaries

            -number of mitochondria many

            -trunk/lower limbs and back

fast oxidative (FO) fibers, type IIa

intermediate to slow and fast twitch

fast glycolytic (FG) fibers, type IIb

- these are large in size, aerobic, and can produce maximal tension

-but only a short period of time

-use atp fastly

- sparse use concentration of capillaries

-number of mitochondria few

-upper limbs

 muscle hypertroph

muscle hypertrophy

increase of size tissue due increase the size of the cell

muscle atrophy

lack of use, wasting in muscle that reduces fiber size. Ex. Cast on limb( a lot smaller than regularly)

Isometric muscle contractions

Muscle length is constant. Tension is produced.

Isotonic muscle contractions

Muscle length is changing as it is doing the work.

Concentric contraction

tthe muscle is shortening

cle is shor

Eccentric contraction

muscle length is changing as its doing work

Agonist

prime mover, major muscle that produces a movement upon contraction.

Antagonist

Muscle is whose action oppose the agonist.

Synergist

Muscle that assist or helps the agonist.

Fibromyalgia

unexplainable, chronic muscle pain

Treatment: Antidepressants, exercise, pain relievers

Muscular Dystrophy

inherited disease characterized by progressive deterioration of muscle tissue.

                  Example: winged Scapulae and scoliosis

-results in atrophy of the affected muscle

-muscle fibers are replaced by fibrous connective and fatty tissue

-no cure but experimental stem cells treatments are helpful

Myasthenia Gravis

Autoimmune disease in which antibodies are produced that attach to the acetylcholine receptors on the sarcolemma, thus blocking or reducing stimulatory effect of the neurotransmitter.

 Symptoms-ptosis, muscle weakness, double vision, difficulty swallowing

Treatments-steroids, immunosuppressants, surgery

Cramps

Involuntary painful, sustained contractions of muscle.

-Cause unknown, but maybe due to lactic acid buildup, dehydration, or calcium deficiencies

-can also be caused by severe blow to muscle

-treatment-stretching

explain how the name of a muscle can help identify its action, appearance, location, or other special features.

1. Muscle action

2. Specific body regions

3. Muscle attachments

4. Orientation of muscle fibers

5. Muscle shape and size

6. Muscle head/tendons of origin

use appropriate terminology when describing attachments of axial muscles to the axial skeleton

“Superior and inferior attachments” or “proximal and distal attachments”

list four primary functions of axial muscles

1.        Support the head and spinal column.

2.        Used in facial expression, chewing and swallowing.

3.        Aid in breathing

4.        Support and protect abdominal and pelvic organs.

Epicranius

-frontal belly/Frontalis

-  raises Eyebrows

Occipital belly/occipitalis

tenses scalp

Buccinator

compress the check.

Mentalis

• attaches to the lip.

• protruding lower lip is the action of this muscle.

Orbicularis oris

-  circular muscle surrounding mouth.

-  kissing action is the muscle.

zygomaticus major / minor

-cheeck region to the top lip

-When the contract, the pull the corner of the mouth on each side, up and laterally, so superiorly and laterally.

-Contact to make the smiling muscles.

orbicularis oculi

-  Circular muscle surrounding the eye.

-Closes the eye.

-Blinking eye

Platysma

- tenses the skin of the neck.

name the primary muscles of mastication, and outline how each affects mandibular movement

temporalis, masseter

Temporalis

Elevates and retracts mandible.

Masseter

Elevates and protects mandible.

identify the major muscles that move the head and neck, their general locations, and their actions

sternocleidomastoid, scalene muscles, splenius capitis and cervicis, longissimus capitis, semispinalis capitis, levator scapulae.

Anterior lateral region

Sternocleidomastoid: attaches to the mastoid process of temporal bone, attaching to the sternum, attaching to the clavicle.

Scalene muscles: deep and laterally to the sternocleidomastoid.

Splenius capitis: deep and kind of upper neck region.

   * these help to flex and laterally move the head

Posterior neck muscles

Cervicis

Longissimus capitis: runs all the way down to the vertebral column. (deeper)

Semispinalis capitis runs all the way down to the vertebral column.

Levator scapulae: elevates the scapula.

Identify the three groups of muscles that comprise the erector spinae and explain how

they work together to determine posture and vertebral movement.

1.Iliocostalis: most lateral group: composed of cervical, thoracic, and lumbar parts. Run from ilium to ribs.

2.Longissimus: composed of capitis, cervical, and thoracic parts. Run from neck to

Vertebral column

3. Spinalis:  most medial group: attached to a spinous process of vertebrae composed of cervical and thoracic parts. Run from neck to Vertebral column

* These muscle help keep the spine up right

name the three primary muscles of respiration and explain their functions

External Intercostals: Elevates rib during inhalation

Internal intercostals: depresses ribs during forced exhalation.

Diaphragm: enlarges thoracic cavity during inhalation

Diaphragm

-most important muscle for breathing

-Dome shaped with central canal

-diaphragm contraction also increases the intra-abdominal pressure

-Important affect for urination, defecation, childbirth, movement of venous blood

list the four pairs of muscles that form the abdominal wall.

1.External Oblique: superficial, lateral muscle; fiber directed inferomedial

2. Internal Oblique: deep to external oblique; fibers directed superomedial.

3. Transverse abdominis: deepest of lateral; fibers directed horizontally

4. Rectus abdominis: long, anterior muscle connecting sternum to pubic bone into divide into four muscle segments.

describe the major functions of the Nervous System

1. Collect information: sensory receptors in PNS detect changes in environment; relay information to CNS

2. Process and evaluate information: CNS determines required response

3. Initiate response: CNS initiates impulses that PNS carries to effectors (muscles        or glands) to react to changes in environment.

identify the structures of the central nervous system (CNS) and peripheral nervous system (PNS) (structural classification)

Central NS (CNS)- Brain and spinal cord

Peripheral NS (PNS)– Cranial nerves, spinal nerves, ganglia.

identify and describe the specific structures and functions of the sensory (afferent) nervous systemand the motor (efferent) and nervous system (functional classification)

Sensory nervous system – detects stimuli and transmits information from receptors to the CNS

Motor nervous system- Initiates and transmits information from CNS to effectors

compare and contrast the somatic sensory and visceral sensory components of the sensory nervous system.

 Somatic motor- effectors are skeletal muscles and are voluntary controlled.

 Visceral Sensory- involuntarily controlled, effectors are cardiac muscle and glands. Includes heart rate and breathing. Things that happen automatically.

recognize neurons and glial cells as two different cell types associated with the nervous system

Neurons- electrically excitable. Information transferer

Glial Cells- long blue cells, they are the helper cells for neurons. (Support and protection for neuron)

list and describe 4 general characteristics of neurons

Neurons- electrically excitable.

·      High metabolic rate

·      Long-lived, non-mitotic

·      Excitable: cable of generating electrical signals in response to stimuli

·      Conductivity: can propagate electrical signals to organs and other neurons

identify and describe the structural elements of neurons: cell body, dendrites, axon hillock, axon

cell body- roundish part of the neuron

dendrites- protrusions on cell body, bring information in.

axon hillock – region where the axon connects to the cell body is the axon hillock.

axon- tail of neuron

·      Classification based upon number of processes emantating from the cell body.

o   Unipolar: one process from cell body

o   Bipolar: two processes

o   Multipolar: multiple protrusions from cell body (most Neurons)

indicate which parts of a neuron receive inputs and which part transmits a nerve impulse (output)

Dendrites-receive inputs (signles) from other neurons        

Axons- transmits nerve impulses to other cells (output)

compare and contrast the 3 structural classifications of neurons (unipolar, bipolar, multipolar) versus the 3 functional classifications of neurons (sensory/afferent, motor/efferent, interneurons)

Sensory- conducts nerve impulses from body to CNS (Unipolar or bipolar)

Motor- conducts nerve impulses from CNS to muscles or glands. (Multipolar)

Interneuron- Found only in CNS; facilitates communication between motor and sensory neurons. (Multipolar)

describe 5 characteristics of glial cells

·      Neuroglia (glial cells) protect and nourish neurons

·      Found in both CNS (4 types) and PNS (2 types)

·      Smaller and more numerous than neurons

·      Capable of mitosis

·      Brain tumors are more likely to be derived from glial cells than neurons.

Astrocytes

Pavascular feet from blood brain barrier. Most abundant in CNS.

            Function: help prevent toxins from entering CNS

Ependymal cells

Ciliated cuboidal epithelial cells that line ventricles of the brain and central canal of spinal cord.

            Function: Assist in production and circulation of CSF

Microglial cells

Small cell with slender branches from cell body. Least common type of glia cell.

            Function: float around CNS and Engulf debris

Oligodendrocytes

Rounded, bulbous cell with slender cytoplasmic extension; extensions wrap around CNS axons.

            Function- Produce Myelin which is an insulator of electrical activity.

Satellite cells

Flattened cell clustered around neural cell bodies in a ganglion.

Function-regulate fluid composition around neuron cell bodies. And monitor environment.

Neurolemmocytes/Schwan cells

Flattened cell wrapped around a portion of an axon in PNS.

Function- Produce myelin. And help axon regenerates

define myelination and its purpose

  Myelination it is the process of wrapping the Axon with a myelin sheath to electrically insulate it

§  It is fatty substance to help protect Axon and speed up communication.

compare and contrast how myelination occurs in the CNS and PNS

Oligodendrocytes (CNS) and Neurolemmocytes (PNS) they both produced myelin to help myelinate the Axon of the neuron. The difference is in location and which gial cells goes with what.

Saltatory conduction

is when an impulse jumps from 1 neurofibrillary node to another. * Produced faster than unmyelinated axons.

Continuous conduction

unmyelinated axons that propagate impulses.

Neurons

individual nerve cells that transmit signals.

Nerves

A cable -like bundle of parallel axons that carry information throughout the body.

describe the structure of a typical nerve

Epineurium-connective tissue surrounding a single Axon.

Perineurium-connective tissue surrounding a bundle of axons.

Endoneurium-connective tissue surrounding entire nerve

explain how the structures associated with synapses (presynaptic neuron, synaptic knobs, postsynaptic neuron) facilitate information flow between two neurons or between a neuron and an effector.

Synapses- specialized junctions between two neurons or between a neuron and a muscle cell or gland cell.

presynaptic neuron- Synaptic knobs at the endings for sending signal.

Synaptic knobs- knobs at synapses

Synaptic cleft- space between both neuron cells

Postsynaptic neuron-a nerve cell that receives signals from another neuron.

Multiple sclerosis

Auto Immune disease where the immune system is attacking myelin on axons, that can affect the CNS.

Amyotrophic latera

neurodegenerative disease affecting various motor neurons. Loss of function leads to muscle weakness, atrophy, and spastic paralysis. 

identify and describe the four major parts of the adult brain

Cerebrum- bulk of the brain

Diencephalon- deep region in the brain

Brainstem- internal structure

Cerebellum- posterior portion of brain

Gyri

Bumps of the ridges or raised areas.

Sulci

indentation or grove

Fissure

a narrow crack

describe the composition and arrangement of the gray matter and white matter in the CNS.

Gray matter- motor neuron and interneuron cell bodies, dendrites, unmyelinated axons.

Cerebral cortex, which covers surface of most of adult brain. Superficial region.

White matter- Made up of myelinated axons.Deep to gray matter of cortex.

list the 3 meninges (pia mater, arachnoid mater, dura mater) and describe their anatomical and functional characteristics.

o   Epidural space: space superficial to dura

Dura mater- tough, strong superficial layer of brain.

o   Subdural space: space below the dura mater

Arachnoid mater- web like layer intermediate to pia matter and dura matter.

o   Subarachnoid space: space deep to arachnoid matter. Contains CSP

Pia mater- delicate layer adhered to the brain and spinal cord. Deepest layer.

identify the four ventricles in the brain and describe their locations

Ventricles – 4 spaces of cavities within the brain, filled with spinal fluid.

Two lateral- one in each cerebral hemisphere

Third ventricle- in diencephalon

o   cerebral aqueduct- leads to 4^th ventricle.

Fourth ventricle – between pons and cerebellm

o   merges with central canal of spinal cord

other info.

Septum pellucidum- thin tissue

Interventricular Forman-hole in-between ventricles.

describe the general functions of cerebrospinal fluid (CSF)

Buoyancy - upward force exerted by a fluid

Protection

Environmental Stability