3 - Introduction to Organ Systems 1

8/11/2019 3 - Introduction to Organ Systems 1

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CARDIOVASCULAR SYSTEM

The human cardiovascular system is composed of a heart whichpumps blood through a closed system of blood vessels. The heart

is composed mostly of cardiac muscle, or myocardium. Its primaryfunction is to transport nutrients, water, gases, wastes, andchemical signals throughout the body. More information on theheart as a pump, blood ow and control of blood pressure, andcomponents of blood will be discussed in related pages.

The cardiovascular system transports materials throughout thebody:1. Materials entering the body, such as oxygen via the lungs andnutrients and water via the intestinal tract, are carried to all cells.

. Materials moved from cell to cell !intercellular communication"including:a" wastes products from some cell cells to the liver for processing#b" immune cells that are present in the blood continuously forother cells,c" hormones from endocrine cells to their target cellsd" stored nutrients from liver and adipose tissue to all cells.$. Materials that are expelled from the body, such as metabolicwastes, heat, and carbon dioxide that are removed via the

%idneys, s%in, and lungs, respectively.

&s a general overview, the cardiovascular system is composedof the heart, the blood vessels !or vasculature", and the cells andplasma of the blood.1. &rteries are blood vessels that carry blood away from the heartand veins return the blood to the heart. & system of valves in theheart and veins ensures that the blood ows in one direction.. The heart is anatomically divided into two halves by a centralwall, or septum, into left and right halves. 'ach half is composed

of an atrium which receives blood returning to the heart and aventricle that pumps the blood out into the blood vessels thatserve the body. The atria and ventricles and exiting blood vesselsare separated by closable valves. (unctionally, the heart servesas a pump in series that generates pressure to propel the bloodthrough the system.


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$. In the lungs oxygen is pic%ed up and carbon dioxide is expelled.The pulmonary circulation goes from the right side of the heart!deoxygenated blood" and returns it to the left side of the heart,with oxygenated blood.

). The systemic circulation consists of the vessels that go fromthe left side of the heart to the tissues and bac% to the right sideof the heart.

The systemic circulation and the pulmonary circulation can betraced together:*eoxygenated blood returning from body enters the heart in theright atrium. (rom the right atrium the blood passes through thetricuspid valves to enter the right ventricle. The blood is thenpumped into the pulmonary arteries, passing the pulmonic valves,

where it goes to the lungs. &fter becoming oxygenated in thelung+s capillaries, the blood is carried by the pulmonary veins tothe left atrium. It then passes through the bicuspid or mitralvalves into the left ventricle, where it is pumped into the aortathrough the aortic valves. The aorta branches into smaller andsmaller arteries that nally lead to capillary beds in the tissue.-ere oxygen is exchanged for carbon dioxide and returned viaveins which oin into the inferior vena cava !veins coming fromthe lower body" and superior vena cava !from the upper body".

The I/0 and the /0 empty into the right atrium.

LYMPHOID SYSTEM

The lymphoid system thus constitutes a sort of 2overow3 systemthat provides for the drainage of surplus tissue uid and lea%edplasma proteins to the bloodstream, as well as for the removal ofdebris from cellular decomposition and infection. The importantcomponents of the lymphoid system are

Lympa!i" ple#$ses%networ%s of lymphatic capillaries thatoriginate blindly in the extracellular !intercellular" spaces ofmost tissues.

Lympa!i" vessels!lymphatics", a nearly body wide networ%of thin4walled vessels that have abundant lymphatic valves.5ymphatic capillaries and vessels occur almost everywhereblood capillaries are found, except for example, teeth, bone,


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bone marrow, and the entire central nervous system. !'xcesstissue uid here drains into the cerebrospinal uid."

Lymp!5.lympha,clear water", the tissue uid that enterslymph capillaries and is conveyed by lymphatic vessels. 6sually

clear, watery, and slightly yellow, lymph is similar incomposition to blood plasma.

Lymp no&es%small masses of lymphatic tissue locatedalongthe course of lymphatic vessels through which lymph is lteredon its way to the venous system. 5ymphocytes reside in thelymph node.

Lympo"y!es%circulating cells of the immune system thatreact against foreign materials. !T7 8 lymphocytes".

Lympoi& organs%includes all the structures dedicated to thecirculation and production of lymphocytes, such as the thymus,red bone marrow, spleen, tonsils.

The smaller lymphatic vessels oin to form to larger and theseenter into large collecting vessels, called lymphatic trun%s, whichunite to form either the right lymphatic duct or the thoracic duct.

Te rig! lympa!i" &$"!drains lymph from the body9s right

upper uadrant !right side of head, nec%, and thorax plus theright upper limb". &t the root of the nec%, it enters the unction ofthe right internal ugular and right subclavian veins, the rightvenous angle.

' Te !ora"i" &$"! drains lymph from the remainder of thebody. The lymphatic trun%sdraining the lower half ofthe bodymerge in the abdomen, sometimes forming a dilated collectingsac, the cisterna chyli. (rom this sac !if present", or from themerger of the trun%s, the thoracic duct ascends into and thenthrough the thorax to enter the left venous angle

&lthough this is the typical drainage pattern of most lymph,lymphatic vessels communicate with veins freely in many parts ofthe body. 0onseuently, ligation of a lymphatic trun% or even thethoracic duct itself may have only a transient e;ect as a new
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pattern of drainage is established through more peripherallymphatico venous


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distant from the original or primary tumor". Metastasis occurs byone of three ways:

1. *irect seeding of serous membranes of bodycavities..5ymphogenous spread !via lymphatic

vessels".$.-ematogenous spread !via blood vessels".It issurprising that often even a thin fascial sheet or serousmembrane deects tumor invasion. -owever, once amalignancy penetrates into a potential space, the directseeding of cavities


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Lymphangitisand lymphadenitisare secondary inammations oflymphatic vessels and lymph nodes, respectively. Theseconditions may occur when the lymphoid system is involved inchemical or bacterial transport after severe inury or infection.

The lymphatic vessels, not normally evident, may becomeapparent as red strea%s in the s%in, and the nodes becomepainfully enlarged. This condition is potentially dangerousbecause the uncontained infection may lead to septicemia!bloodpoisoning". Lymphedema,a locali=ed type of edema, occurs whenlymph does not drain from an area of the body. (or instance, ifcancerous lymph nodes are surgically removed from the axilla!armpit", lymphedema of thelimb may occur.

Respira!ory sys!em

Respiration consists of:

1. Breathing(inspiration and expiration),

2. Gaseous Exchange(exchange of gases

between the lungs/blood and blood/tissues and

ice!ersa).

"t is controlled by the #utonomic $erous %ystem

(#$%), more specifically by the &edulla 'blongata.

2asi" S!r$"!$re o* !e Respira!ory Sys!em

ere is the simplest possible statement of the structure of the respiratory system as

a flow!chart indicating the route by which oxygen flows into the body ia the

airways and traels to the surfaces at which gaseous exchange with tissues occurs:

Upper Respiratory Tract :

NARES


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NASO PHARYNX

EPIGLOTTIS(larynx

TRA!HEA

Lo"er Respiratory Tract :

TRA!HEA

(#I$I!ATES INTO % #RON!HI

#RON!HIOLES

UPPER LO&ER

AL'EOLAR U!TS AL'EOLAR U!TS

AL'EOLAR SA!S AL'EOLAR SA!S

LO3ER RESPIRATORY TRACT


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Memorable Facts about the Human Respiratory System

here are two lungs in the body consisting of * million aleoli that

constitutes the total surface area of about 2 tennis courts (per normal adult).

#ll of the blood in the body circulates through the lungs each time it passes

around the body. "f laid end!to!end the capillaries of the lungs would stretch for approx. ++

miles (- m).

Diges!ive sys!em

he digestie system is made up of the digestie tracta series of hollow organs

0oined in a long, twisting tube from the mouth to the anusand other organs that

help the body brea down and absorb food (see figure).

'rgans that mae up the digestie tract are the mouth, esophagus, stomach, small

intestine, large intestinealso called the colonrectum, and anus. "nside these

hollow organs is a lining called the mucosa. "n the mouth, stomach, and small

intestine, the mucosa contains tiny glands that produce 0uices to help digest food.

he digestie tract also contains a layer of smooth muscle that helps brea down


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food and moe it along the tract.

wo solid digestie organs, the lier and the pancreas, produce digestie 0uices

that reach the intestine through small tubes called ducts. he gallbladder stores the

lier3s digestie 0uices until they are needed in the intestine. 4arts of the nerousand circulatory systems also play ma0or roles in the digestie system.

Why is digestion important

5hen you eat foodssuch as bread, meat, and egetablesthey are not in a form

that the body can use as nourishment. 6ood and drin must be changed into smaller

molecules of nutrients before they can be absorbed into the blood and carried to

cells throughout the body. 7igestion is the process by which food and drin are

broen down into their smallest parts so the body can use them to build andnourish cells and to proide energy.

Renal Sys!em

"ntroduction to the renal system

8omponents of the renal system

9idneys and ureters

ladder

;rethra

"ntroduction to the renal system

he renal systemconsists of all the organs inoled in the formation and release

of urine. "t includes the idneys,ureters,bladderand urethra.

Function o! renal system1. Maintenance of electrolyte concentration in '0(!'>T?&0'5565&? (56I*". Maintenance of water balance$. 'xcretion of waste products

). ?egulation of blood pressure@. ?egulation of red blood cell concentrationA. &cid base balance

Components of the renal system

"idneys and ureters

.
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he idneys are large, bean!shaped organs towards the bac of the abdomen

(belly).

he idney can be diided into two distinct regions. here is an outer red!brown

part (cortex) and inner lighter coloured part (medulla). he cortexis made up of

special units called corpuscles, nephrons, and a system of straight and cury

collecting tubules supplied by many blood essels. "n the outer part of the idney,

there are many nephrons which act as filtering units.


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he male urethra runs from the bladder to the tip of thepenis.

he female urethra. "t is a tube running from the bladder nec and opening into an

external hole located at the top of the aginalopening. #s the female urethra is

shorter than the male urethra, it is more liely to get infectionsfrombacteriain the

agina.

REPRODUCTIVE SYSTEM

'n of the ma0or organ systemsof the body. he chief function of the reproductie

system is to ensure surial of the species. 5hat follows applies principally

to ertebratereproduction, especially human reproduction.

'ther systems in the body, such as the endocrineand urinarysystems, wor

continuously to maintain homeostasisfor surial of the indiidual. #n indiidual

may lie a long, healthy, and happy life without producing offspring, but if thespecies is to continue, at least some indiiduals must produce offspring.

5ithin the context of producing offspring, the reproductie system has four

functions:

o produce oa(eggs) and spermcells

o transport and sustain these cells

o nurture the deeloping offspring

o produce hormones

hese functions are diided between the primary and secondary, or accessory,

reproductie organs. he primary reproductie organs, or gonads, consist of

the oariesand testes. hese organs are responsible for producing the egg and

sperm cells @ the gametes@ and for producing hormones . hese hormones

function in the maturation of the reproductie system, the deelopment of sexual

characteristics, and hae important roles in regulating the normal physiology of thereproductie system. #ll other organs, ducts, and glands in the reproductie system

are considered secondary, or accessory, reproductie organs. hese

structures transport and sustain the gametes and nurture the deeloping offspring.

6or more details, see:

&ale reproductie system
http://www.virtualcancercentre.com/Medical_Dictionary.asp?termid=992http://www.virtualcancercentre.com/Medical_Dictionary.asp?termid=977http://www.virtualcancercentre.com/Medical_Dictionary.asp?termid=1176http://www.virtualcancercentre.com/Medical_Dictionary.asp?termid=267http://www.daviddarling.info/encyclopedia/O/organ_system.htmlhttp://www.daviddarling.info/encyclopedia/V/vertebrate.htmlhttp://www.daviddarling.info/encyclopedia/E/endocrine_system.htmlhttp://www.daviddarling.info/encyclopedia/U/urinary_system.htmlhttp://www.daviddarling.info/encyclopedia/H/homeostasis.htmlhttp://www.daviddarling.info/encyclopedia/O/ovum.htmlhttp://www.daviddarling.info/encyclopedia/S/sperm.htmlhttp://www.daviddarling.info/encyclopedia/H/hormone.htmlhttp://www.daviddarling.info/encyclopedia/G/gonad.htmlhttp://www.daviddarling.info/encyclopedia/O/ovaries.htmlhttp://www.daviddarling.info/encyclopedia/T/testes.htmlhttp://www.daviddarling.info/encyclopedia/G/gamete.htmlhttp://www.daviddarling.info/encyclopedia/R/reproductive_system.htmlhttp://www.daviddarling.info/encyclopedia/R/reproductive_system.htmlhttp://www.daviddarling.info/encyclopedia/M/male_reproductive_system.htmlhttp://www.daviddarling.info/encyclopedia/R/reproductive_system.htmlhttp://www.daviddarling.info/encyclopedia/R/reproductive_system.htmlhttp://www.virtualcancercentre.com/Medical_Dictionary.asp?termid=992http://www.virtualcancercentre.com/Medical_Dictionary.asp?termid=977http://www.virtualcancercentre.com/Medical_Dictionary.asp?termid=1176http://www.virtualcancercentre.com/Medical_Dictionary.asp?termid=267http://www.daviddarling.info/encyclopedia/O/organ_system.htmlhttp://www.daviddarling.info/encyclopedia/V/vertebrate.htmlhttp://www.daviddarling.info/encyclopedia/E/endocrine_system.htmlhttp://www.daviddarling.info/encyclopedia/U/urinary_system.htmlhttp://www.daviddarling.info/encyclopedia/H/homeostasis.htmlhttp://www.daviddarling.info/encyclopedia/O/ovum.htmlhttp://www.daviddarling.info/encyclopedia/S/sperm.htmlhttp://www.daviddarling.info/encyclopedia/H/hormone.htmlhttp://www.daviddarling.info/encyclopedia/G/gonad.htmlhttp://www.daviddarling.info/encyclopedia/O/ovaries.htmlhttp://www.daviddarling.info/encyclopedia/T/testes.htmlhttp://www.daviddarling.info/encyclopedia/G/gamete.htmlhttp://www.daviddarling.info/encyclopedia/R/reproductive_system.htmlhttp://www.daviddarling.info/encyclopedia/R/reproductive_system.htmlhttp://www.daviddarling.info/encyclopedia/M/male_reproductive_system.html


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6emale reproductie system

Male Reproducti$e System

he male reproductie system,

lie that of the female

(see female reproductie

system), consists of thoseorgans whose function is to

produce a new indiidual, i.e.,

to accomplish reproduction.

his system consists of a pair of

testes and a networ of

excretory ducts (epididymis, ductus deferens (as deferens), and e0aculatory ducts),

seminal esicles, theprostate gland, the bulbourethral glands, and the penis.

testes

duct system

accessory glands

penis

male sexual response and hormonal control
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Female reproducti$e system

he organs of the female

reproductie system produce

and sustain the female sex

cells (egg cellsor oa), transport these cells

to a site where they may be

fertili=ed by sperm, proide a

faorable enironment for the

deeloping fetus, moe the fetus to the outside at the end of the deelopment

period, and produce the female sex hormones . he female reproductie system

includes the oaries, 6allopian tubes, uterus, agina, accessory glands, and external

genital organs.

En&o"rine Sys!em

he endocrine systemis a systemof glands, each of which secretes a type

of hormoneinto the bloodstream to regulate the body. he endocrine system is an

information signal system lie the nerous system. ormones regulate many

functions of an organism, including mood, growth and

deelopment, tissuefunction, and metabolism. he field of study that deals with

disorders of endocrine glands is endocrinology, a branch of internal medicine.

hey are two types of glands endocrine and exocrine glands.


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posterior pituitary, pancreas, adrenals, pineal, and gonads. #lso called ductless

gland

EXOCRINE GLANDS

# gland that secretes a substance out through a duct. he exocrine glands include

the saliary glands, sweat glands and glands within the gastrointestinal tract. he

exocrine glands are the Bglands of external secretion.B

he endocrine system is made up of a series of ductless glandsthat produce

chemicals called hormones..

"n addition to the speciali=ed endocrine organs mentioned aboe, many otherorgans that are part of other body systems, such as

the idney, lier, heartand gonads, hae secondary endocrine functions. 6or

example the idney secretes endocrine hormones such as erythropoietinand renin.
http://en.wikipedia.org/wiki/Ductless_glandhttp://en.wikipedia.org/wiki/Hormoneshttp://en.wikipedia.org/wiki/Kidneyhttp://en.wikipedia.org/wiki/Liverhttp://en.wikipedia.org/wiki/Hearthttp://en.wikipedia.org/wiki/Gonadhttp://en.wikipedia.org/wiki/Erythropoietinhttp://en.wikipedia.org/wiki/Reninhttp://en.wikipedia.org/wiki/Ductless_glandhttp://en.wikipedia.org/wiki/Hormoneshttp://en.wikipedia.org/wiki/Kidneyhttp://en.wikipedia.org/wiki/Liverhttp://en.wikipedia.org/wiki/Hearthttp://en.wikipedia.org/wiki/Gonadhttp://en.wikipedia.org/wiki/Erythropoietinhttp://en.wikipedia.org/wiki/Renin


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'R&'$


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9ID)EY A&renal glan&sA&renal me&$lla

[Adrenal cortex) (Catecholamines)

Parathyroid Repro&$"!ive Sys!em

Ovarian follicle/

Corpus luteum

Testes

Se"re!e& ormone

?enin.Primarily0

'rythropoietin.EPO0

0alcitriol.:%;


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I)TE5UME)TARY SYSTEM

ecause the sin (?.integumentum,a coering) is readily accessible and is one of

the best indicators of general health, careful obseration of it is important in

physical examinations. "t is considered in the differential diagnosis of almost eerydisease. he sin proides:

Heat regulation

Sensation

Synthesis and storageof itamin 7.

he s%in,the bodyDs largest organ, consists of the epidermis, a superficial cellular

layer, and the dermis, a deep connectie tissue layer.

he epidermisis a eratini!ed e"ithelium!that proides a protectie outer

surface#he epidermis has no blood essels or lymphatics. he a$ascular

e"idermisis nourished by the underlying $asculari!ed dermis#he sin is also

supplied with afferent nere endings that are sensitie to touch, irritation (pain),

and temperature. &ost nere terminals are in the dermis, but a few penetrate the

epidermis.

he dermisis a dense layer of interlacing collagenand elastic fibers#hese fibers

proide sin tone and account for the strength and toughness of sin.

he sin also contains many speciali=ed structures. he deep layer of the dermis

contains hair %ollicles,with associated smooth arrector muscles and sebaceous

glands. 8ontraction of the arrector muscles o! hairs(?.musculi arrector "ili)

erects the hairs, causing goose bumps. 8ontraction of the arrector muscles causes

compression of the sebaceous glands and helping them to secrete their oily product

onto the sin surface. he eaporation of the watery secretion (sweat) of thes&eat

glandsfrom the sin proides a thermoregulatory mechanismfor heat loss(cooling). #lso inoled in the loss or retention of body heat are the small arteries

(arterioles) within the dermis. hey dilate to fillsu"er%icial ca"illary 'edsto

radiate heat (sin appears red) or constrict to minimi=e surface heat loss (sin,

especially of the lips and fingertips, appears blue). 'ther sin structures or
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eins. 8yanosis is especially eident where sin is thin, such as the lips, eyelids,

and deep to the transparent nails.

Burnsare caused by thermal trauma, ultraiolet or ioni=ing radiation, or chemical

agents. urns are classified, in increasing order of seerity, based on the depth ofsin in0ury

(st)degree *su"er%icial+ 'urn(e.g., sunburn): damage is limited to the

epidermis

nd)degree *"artial)thicness+ 'urn-epidermis and superficial dermis are

damaged with blistering (superficial 2nd degree) or loss (deep 2nd degree

.rd)degree *%ull)thicness+ 'urn-the entire thicness of the sin is damaged

and perhaps underlying muscle
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Documents

3 - Introduction to Organ Systems 1