Session 2 Integument & sensory system

8/7/2019 Session 2 Integument & sensory system

1/87

INTEGUMENT AND

SENSORY NERVOUS

SYSTEM

SESSION 2

Notes (Pg 14-30)Moore (Pg 12-18; 45-56)


2/87

INTRODUCTION

Concepts and terminology

to describe the structure and functions variousstructures belonging to systems of the body.

Tissue types Amount intercellular

substance-white unelastic fibers

-yellow elastic fibers

appearance &

function of cells.Cells = buildingblocks.


3/87

Name the four principal tissue types:

characteristics, functionsand example of each type.

OUTCOME - 1


4/87

TISSUE TYPES

Epitheleal tissueprotects @ wear &

tear

Connective tissue

Nervous tissue

Muscle tissue

1. True epithelium(protects)

2. Mesothelium (lines)

3. Endothelium


5/87

Connectivetissue

Nervous

tissue

1. True epithelium2. Mesothelium3. Endothelium

a lining membrane ofthe body tracts thatopen to the exterior

Digestive, respiratory &urogenital tracts

Exocrine glands

EpidermisMucosa

TISSUE TYPES

Epithelealtissue

Muscletissue


6/87

Epithelial

Connective

Nervous

Muscle

1. True epithelium2. Mesothelium

3. Endothelium

serous liningmembrane for large

cavities of body

slipperylessens friction.

PleuraPericardiumPeritoneum

TISSUE TYPES


7/87

Epithelialtissue

Bind

Senuwee

Spier

1. True epithelium2. Mesothelium3. Endothelium

inner lining of walls ofblood and lymph

vessels & heart,reduces friction, helpsprevent blood clotting.

TISSUE TYPES (Pg 15)


8/87

Define: pleura, pericardium &

peritoneum, epidermis,

mucosa, subcutaneous, skin

ligaments, fascia, aponeurosis,

intermuscular septa, differenttypes of muscles.

OUTCOME - 2


9/87

TISSUE TYPES

Connective tissue (Pg 16) Packing and support material. NB role in repairing

injuries scar tissue.

Cells far apart, large quantities of intercellular

substance. Varying quantities of fibres present in

intercellular substance.a) Areolar connective tissue

b)Adipose tissue

c)Dense connective tissue (tendons, aponeuroses,

ligament, deep fascia, intermuscular septa)

d)Cartilage

e)Bone ( connective tissue + inorganic calcium)

f)Haemopoetic tissue


10/87

Ligament / Tendon / Aponeurosis

Ligament: attach bone to bone

(stability; limits movement).

Tendon: attaches muscle to bonefused with periosteum

(non-elastic white fibers).

Aponeurosis: plate-like tendon

broader attachment


11/87

superficial fascia

deep fascia: dense

connective tissue layer

intermuscular septa: groups ofmuscles with similar functionssharing same nerve supply arelocated in fascial compartments

spread infection/CA

Fascia & intermuscular septa


12/87

BURSA(e) (PURSE)

Closed sacs of serous membrane (connective

tissue membrane capable of secreting fluidto lubricate a smooth internal surface).

collapsed with thin layer of lubricating fluid

Locations subject to friction

Visceral layer and parietal layer

Around viscera or tendonsWhen walls are interrupted at any point, or when afluid is secreted or formed within them in excessthey become realized spaces = pathologicalcondition.


13/87

TYPES OF BURSAE

Subcutaneous bursae skin and bone

Subfascial bursae beneath deep fascia

Subtendinous bursae movement oftendon over bone

Synovial tendon sheaths elongated

bursae around tendons


14/87

Synovial sheaths

Outer

parietallayer

Inner visceral layer

Tendon

Parietallayer

Visceral

layer

Space filled with

synovial fluid


15/87

Pleura, pericardium & peritoneum

Bursas enclose structures like the heart, lungs,

abdominal viscera and tendons.

Parietal & visceral layers

Smooth gliding movement to structures

Heart (not inside but enclosed by bursa)pericardium;

Lungs- pleura;

Abdominal organs peritoneum.


16/87

16

Serouspericardium-Parietal layer-Visceral layer

Pericardial sac = Pericardium


17/87

17

Pleura


18/87

Peritoneum

Ti t


19/87

Tissue types

Muscluar tissues

Skeletal / striatedvoluntary muscle

Contractions fast & ofshort durationmuscles attach to

skeleton.

Cardiac muscle.

Contractions occur

rhythmically.

Visceral / nonstriatedinvoluntary muscleContraction slow & of

longer duration. In holloworgans (alimentary canal,

walls of bloodvessels)


20/87

Tissue types

Nervous tissue

Detect changes in external & internal environments

Bring about appropriate responses in muscles,organs and glands


21/87

Describe the general

composition of the nervous

system as well as the sensory

component of the nervous

system.

OUTCOME - 3


22/87

STRUCTURAL SUBDIVISION


23/87

BrainCranialnerves

Central / Peripheral nervous system

Spinal cord

Spinalnerves


24/87

Functional division of theNervous system

Somatic Autonomic


25/87

CENTRAL NERVOUS SYSTEM

BRAIN

CerebrumCerebellum

BRAINSTEM

MidbrainPonsMedulla Oblongata

SPINAL CORD


26/87

PERIPHERAL NERVOUS SYSTEMSpinal- and Cranial nerves

AUTONONOMICSimpathetic (fight &flightParasimpathetic

SOMATICSensories (afferent)

(sensasie)Motories (efferent)(beweging)


27/87

Define the following terms:neuron & neuroglia.

receptor & effector

axon and dendritesynapse

nerve and nerve fiber

somatic & visceral neurons

central & peripheral nervous system

OUTCOME - 4


28/87

THE NEURON

Structural and functional unit of nervous

system Consists of:

- Cell body

- Dendrites (receive impulses)- Axons (carry impulses away)

- Myelin sheaths ( velocity of impulseconduction)

Synapses = communication areas betweenneurons

Neurotransmitters = chemical agents that

control impulse conduction


29/87

The structure of the neuron

Nucleus

Cell body

Dendrite

Axon

Myelin sheath

Impulses to cell body

Impulses awayfrom cell body


30/87

A synapse

Direction of

nerve impulse

Synapticcleft

Post-synaptic neuron

Receptors forneurotransmitter


31/87

NEUROGLIA

5x more abundant than neurons Support, insulate, nourish neurons

In CNS:

- oligodendroglia- astrocytes

- ependymal cells

- microglia In PNS:

- satellite cells

- neurolemma (Schwann cells)


32/87

PERIPHERAL NERVOUS SYSTEM

Conduct impulses to and from CNS Peripheral nerve fibre:

- axon

- neurolemma (myelinated or unmyelinated)- endoneurium

Peripheral nerve:

- bundle ofnerve fibres- connective tissue coverings

- blood vessels

St t f i h l


33/87

Structure of a peripheral nerve

Peripheral nerve

Epineurium

Perineurium

Peripheral

nerve fibreEndoneurium

Myelin sheathAxon

Vasanervorum

Fascicle


34/87

Types of peripheral nerves

-afferent = sensory-impulses from sense organsto CNS)

-efferent = motory

-(impulses from CNS effector organs)


35/87

Afferent (sensory) nerve fibres

Sensory neuron

Impulse

Skin

cross section ofthe spinal cord.


36/87

Efferent (motory) nerve fibres

Motor neuron

Impulse

Muscle


37/87

TYPES PERIPHERAL NERVES

-

CranialExits cranial

cavity viaforaminae (12pairs)

Romannumbers (I-XII)

Spinalexits vertebral column

via intervertebralforaminae (31 pairs)

Letter = spinal cord

segment + numberex. T4

l d


38/87

Spinal cord segments

Cervical

Thoracic

Lumbar

Sacral

Coccygeal


39/87

31 PAIRS OF SPINAL NERVES

8 Pairs of cervical spinal nerves (C1-C8)

12 Pairs of thoracic spinal nerves (T1-T12)

5 Pairs of lumbar spinal nerves (L1-L5)

5 Pairs of sacral spinal nerves (S1-S5)

1 Pair of coccygeal spinal nerves (Co1)


40/87

Grey- and white matter in spinal cord

Whitematter

Greymatter


41/87

STRUCTURE OF A SPINAL NERVE

Posterior (dorsal) root


42/87

Posterior (dorsal) root:

-sensory (afferent) fibers-Cell bodies in dorsal root

ganglia (DRG)


43/87

Anterior (ventral) root:-motor (efferent) fibers

-Cell bodies in ant. horn effector organs.

Receptor / Effector


44/87

Receptor / Effector

Receptor inskin:dermatome

Effector: muscle:

myotome

*Mixedspinalnerve


45/87

STRUCTURE OF A SPINAL NERVE

Motor / sensory nerve refers to majority offibres conveyed by nerve

Dermatome:

= unilateral area of skin innervated by aspinal nerve

Myotome:

= unilateral muscle mass innervated by aspinal nerve

Dermatomes of


46/87

Dermatomes of

the body

Cervical segments

Thoracic segments

Lumbar segments

Sacral segments


47/87

Sensory component

General sensation(touch, pain, temp, pressure

-viscera: normal distension

of a viscus stretch, ischemia)

Special sensations(vision, smell, hearing)

Proprioception(state of contraction of

muscle or position of a joint).

From internal & external environment


48/87

Sensory receptor(pain, touch, etc.on skin or stretchreceptor in musclespindle


49/87

Describe the embrionic

development of the neuraltube and the neural crest.

OUTCOME - 5

Embr o 16 da s old


50/87

Embryo 16 days old

EMBRYONIC DISC


51/87

EMBRYONIC DISC

Second week of human embryonic development 3 germ cell layers:

ectoderm Skin and nervous system

mesoderm Skeletal, muscular and

connective tissue

endoderm Alimentary, respiratory andgenito-urinary

The nervous system develops from ectoderm on dorsum

of embryonic plate.


52/87

E b i i d l t


53/87

3rd week ectoderm thickens to form neural

plate

Neural plate forms oblong depression the

neural-groove. Thickened edges of groove

are neural folds

Neural folds approach each other and fuse

neural tube

Cells of neural fold become separated

neural crest

Embrionic development


54/87

Describe the embrionic

development of the somitesand the migration of the

dermatome and myotome.

OUTCOME - 6

Whil h l b i


55/87

32 day old

Somiteblocks

While the neural tube isforming, the mesodermal layerof embrionic plate forms

segments.

They appear as pairedblocks of mesoderm

which extend from thecaudal end of spinalcord to the brain onboth sides of neuraltube = somites

20 days

Somytes


56/87

Somytes


57/87

Name the structures that

develop from each part of thesomite.

OUTCOME - 7


58/87

32 day old

dermatome dermis of skin

myotome skeletal muscles

sclerotome part of skeleton

32 days old


59/87

Describe the development

of a sensory spinal nerve.

OUTCOME - 8


60/87

Neuralcrest cells:cell body

dendrite

reseptorin skin

axon


61/87

Describe the parts and the

location of the parts of asensory (afferent) neuron.

OUTCOME - 9

Afferent nerve fibres


62/87

Afferent nerve fibres

Sensory neuron

ImpulseSkin

O O


63/87

Describe the composition ofskin and name the major

functions of skin.

OUTCOME - 11

OUTCOME - 10

Name the structures that belong

to the integumentary system

INTEGUMENTARY SYSTEM


64/87

INTEGUMENTARY SYSTEM

Includes skin and its appendages hair, nails

and mammary gland Skin largest organ, one of the best indicators

of general health

Functions: protection,

containment of bodys structures and vitalsubstances,

sensory organ,

heat regulation and

synthesis and storage of vitamin D

The dermis & epidermis


65/87

The dermis & epidermis

Epidermis

Dermis

Subcuta-

neoustissue

Hair

Arrectorm.

Sebaceousgland

Sweat gland


66/87

STRUCTURE OF THE SKIN

Epidermis stratified, keratinized epithelium

horny layer and basal pigmented layer

thickness depends on location

no blood vessels

nourishment from underlying bloodvessels

in the dermis.

sensory nerve ends (touch, pain,

temperature) in dermis, few in epidermis.



67/87

Dermis

connective tissue

(collagen and elastic fibers)

contains

hair follicles (smooth arrector muscles)

sebaceous glands

sweat glands

arterioles

other: hair, nails, enamel of teeth, mammaryglands


Blood & nerve supply


68/87

Blood & nerve supply

Nerve supply:

- afferent nerve ends

- somatic sensation:

- sensitive for touch, pain and temperature

- sympathetic nerve fibers:

- vasodilatation

- vasoconstriction

Blood supply:

- capillary plexuses in dermis

Blood vessels & nerves in skin


69/87

Blood vessels & nerves in skin

Superficialbloodvessels

Cutaneous n.

Afferent n.endings

SUPERFICIAL FASCIA


70/87

= Subcutaneous tissue

Loose connective tissue + fat

Serves as insulation and padding

contains

sweat glands

superficial blood vessels

lymphatic vessels

cutaneous nerves

skin ligaments (attach dermis to deepfascia)

SUPERFICIAL FASCIA

Superficial fascia


71/87

Superficial fascia

Superficialfascia

Sweat gland

Bloodvessels

Lymphvessel

Skin ligament

Cutaneous n.

Skin ligaments (L Retinacula cutis)


72/87

Skin ligaments (L. Retinacula cutis)

Attach deep surface ofdermis to underlyingdeep fascia

OUTCOME 12


73/87

Define a dermatome and a

myotome and describe thedistribution of

dermatomes in the adult.

OUTCOME - 12

Dermatome / Myotome


74/87

Dermatome / Myotome

Area of skin that issupplied by a particularspinal nerve.

Each spinal nervecarries sensoryinnervation for a

specific part of thebody surface.

Group of skeletal

muscles innervated by a

particular spinal nerve

is collectively known as

a myotome.

Dermatomes of


75/87

the body

Cervical segments

Thoracic segments

Lumbar segments

Sacral segments

OUTCOME 15


76/87

Describe the cleavage lines

of the skin and explaintheir importance.

OUTCOME - 15

Tension (cleavage) lines


77/87

Tension (cleavage) lines

The predominant pattern of collagenfibers in the dermis determines the

characteristic tension lines in the skin.

Elastic fibers deteriorate with age

wrinkles and sags.

Spiral longitudinally in limbs,

transversely in neck /trunk.

Incisions parallel to tension lines healwell, laceration across tension line

disrups more collagen may heal with

excessive (keloid) scarring.


78/87

Stretch marks

Pregnancy: damaged collagen fibers in the

dermis

Burns


79/87

Burns1st:damage limited to

epidermis2nd: epidermis &superficial dermisdamaged, blistering,nerve endings damaged;most painfull

3rd: entire thickness of skin / underlying muscleMarked edema, numb, sensory ending destroyed.

Require skin grafting.

E t t f b (% t t l b d

Rule of Nines


80/87

Extent of a burn (% total bodysurface) more significant than

the degree in estimation effecton the well-being of the victim.American Burn

associations classification:Major burn: 3rd degree burnsover 10% of body surfacearea; 2nd degree burns over

35% or any 3rd-degree burnsof face, hands, feet, perineum.

Burn area > 70% of body surface area mortality

rate > 50%

d


81/87

Burn wounds

DEEP FASCIA


82/87

Deep to skin and superficial fascia

Investing fascia (e.g., neurovascular bundles)

Intermuscular septae

(muscle compartments in limbs)

- surrounding fascia attached to bone(limits infection / tumor)

- attachment to some muscles

- blends with periostium no gliding- relatively unyielding muscle pump

- retinaculum - holds tendons in place when

they cross a joint (prevents bow stringing)

Fascial compartments


83/87

Fascial compartments

superficial fascia

deep fascia: denseconnective tissue layer

investing fascia: invest deeper structures

(eg. muscles, neurovascular bundles)

intermuscular septa: groups ofmuscles with similar functionssharing same nerve supply arelocated in fascial compartments

spread infection/CA


84/87

In a few places, the deep fascia gives

attachment to underlying muscles.

In most places muscles are free to glide deep

to the deep fascia

Where deep fascia contacts bone, it blinds

with the periosteum.

Deep fascia surrounding fascial compartments

in the limbs, limits the outward expansion of

the bellies of contracting skeletal muscles.

(see musculovenous pump)

Retinaculum


85/87

Retinaculum

Near certain joints(wrist/ankle), deep fasciabecomes markedlythickened, forming a

retinaculum to holdtendons in place wherethey cross the jointduring flexion andextension, preventingthem from bow stringing.

OUTCOME 14


86/87

Explain the muscle pump

mechanism and the role of

the parts of a muscle

pump in the return of

venous blood from thedependant limbs

OUTCOME - 14


87/87

Deep fascia

Documents

Session 2 Integument & sensory system