copyright 2010 pearson education, inc. chapter 16 tissues, organs, and organ systems organ donation

Copyright © 2010 Pearson Education, Inc.

Chapter 16

Tissues, Organs, and Organ Systems

Organ Donation


16.1 Tissues

Tissues = group of similar cell types that perform a common function.

Four basic types of tissue:1. Epithelial2. Connective3. Muscle4. Nervous


16.1 Tissues - Epithelial Tissue

Epithelium is tightly packed sheets of cells

cover organs and outer surfaces

line insides of hollow organs, vessels, and body cavities.

Figure 16.1

(a) Examples of organs lined with epithelialtissue:

(b) Epithelial cells in skin

Heart and blood vessels

Respiratory tract

Digestive tract

Urogenital tract

Epidermis

(c) Epithelial cells liningthe small intestine


16.1 Tissues - Epithelial Tissue

Epithelia are polar anchored on one surface, but free on another

The free side is typically exposed to the environment or body fluids

Can be single layer or many layers thick

Function in protection, secretion, and absorption

Epithelial cells are continuously sloughing off and are replaced by cell division


16.1 Tissues - Connective Tissue

Connective Tissue Loosely organized and composed of cells

embedded in a matrix Cells

Blood cells, adipocytes, fibroblasts, chondrocytes, osteocytes

Matrix is composed of two things1. Ground substance

Liquid, gel-like, rubbery or solid2. Fibers

Collagen, elastin, reticular fibers



Connective Tissue Usually binds organs or tissues to one another Six different types:

Loose connective tissue Adipose tissue Blood Fibrous connective tissue Cartilage Bone

Copyright © 2010 Pearson Education, Inc. Figure 16.2a


Most widespread tissue in animal body

Matrix composed of collagen and elastin fibers

It is called “loose” because fibers are loosely woven together

Binds epithelia to tissues, pads skin, and holds organs in place

Loose Connective Tissue



Adipose Tissue AKA Fat Primarily adipose

cells; small amount of matrix

Functions Used for storage of

energy (fat) Insulation Padding for organs

Figure 16.2b



Blood Cellular component

red blood cells, white blood cells and platelets

Matrix is the plasma Functions include

carrying oxygen and nutrients; fighting infection

Figure 16.2c

Redblood cell

Platelet

Whiteblood cell

Plasma

(c) Blood



Fibrous Connective Tissue Forms tendons and

ligaments Matrix is collagen

fibers running in parallel

Figure 16.2d

Fibroblastcell

Parallelcollagenfibers

(d) Fibrous connective tissue (tendon)

Copyright © 2010 Pearson Education, Inc. Figure 16.2e

MatrixMatrix

Chondro-cytes

(e) Cartilage(at the end of a bone)


Cartilage Chondrocytes

Secrete rubbery matrix, collagen and elastin

Cartilage cushions joints, forms support for ears and nose

Not vascularized, so takes a long time to heal if injured

Copyright © 2010 Pearson Education, Inc. Figure 16.2f

Matrix

Osteocytes

Centralcanal

(f) Bone


Bone Rigid connective tissue Osteocytes

secrete matrix of collagen fibers and calcium salts

Bone marrow produces blood cells

Body can make use of calcium from bones if dietary levels are too low


16.1 Tissues - Muscle Tissue

Muscle is contractile tissue Long, thin cylindrical cells called muscle

fibers Two proteins – actin and myosin –

interact to cause contraction of muscle fibers

Three types of muscle:1. Skeletal2. Cardiac3. Smooth



Skeletal Muscle Usually attached to bone Produces all voluntary movements Striated Long, thin, cylindrical shape

Figure 16.3aMuscle fiber Nucleus

(a) Skeletal muscle (biceps)

Copyright © 2010 Pearson Education, Inc. Figure 16.3b

(b) Cardiac muscle (heart)

Muscle fiber Nucleus


Cardiac Muscle Only found in

heart tissue Striated involuntary,

undergoes rhythmic contractions to produce heartbeat

Branched, interlocking cells propagate signal to contract almost simultaneously

Copyright © 2010 Pearson Education, Inc. Figure 16.3c

Muscle fiber Nucleus

(c) Smooth muscle (intestine)


Smooth Muscle Not striated Spindle-shaped cells Musculature of

organs, blood vessels, digestive tract

Involuntary Contracts more slowly and for longer than

skeletal muscle


16.1 Tissues - Nervous Tissue

Nervous Tissue Neurons conduct electrical signals Primary cells of the brain and spinal cord Main function of neurons is to:

Sense stimuli Process stimuli Transmit signals

Most cells of nervous system do not undergo cell division


16.1 Tissues - Tissue Donation

Brain death and Tissue Donation Injuries from motor vehicle accidents, burst

blood vessels, and drowning are common causes of brain death Once dead, brain cells cannot recover Tissues can be harvested to help others

> One person’s tissues can improve the lives of as many as 50 people.

Copyright © 2010 Pearson Education, Inc. Figure 16.5

16.2 Organs and Organ Systems

Organs are composed of two or more tissue types Organs that act

together form an organ system

All the organ systems of a body form an organism

Muscle cell

Muscle tissue

Heart organ Circulatory system Organism



Figure 16.8

12 Organ Systems


16.2 Organs and Organ Systems –

The Liver as a Model Organ The liver sits below the

diaphragm comprised of four

lobes associated with the

gall bladder.

Figure 16.6



The Liver as a Model Organ The liver is an important component of the

digestive and the circulatory system As part of the circulatory system, the liver:

Synthesizes blood clotting factors Detoxifies Regulates blood volume Destroys old red blood cells

As part of the digestive system, the liver: Produces bile Metabolizes and stores nutrients



Liver Structure Epithelia

Hepatocytes Lining blood vessels Lining bile ducts

Connective Tissue Loose connective

tissue Kupffer cells


16.2 Organs and Organ Systems - The Liver as a Model Organ

Liver transplants can be made from living donors or from brain dead ones Unlike many organs, liver can regenerate

itself Portion can be taken from living donor and

implanted in patient Liver in donor and patient will regrow to

normal size



The Digestive System

Figure 16.8

Mouth• Teeth reduce the size of food, increasing surface area available for digestion by enzymes.• Amylase enzymes in saliva start breaking down carbohydrates.


16.2 Organs and Organ SystemsThe Digestive System

Figure 16.8

Esophagus• The esophagus transports food to stomach by rhythmic waves of muscle contractions called peristalsis.



Figure 16.8

Stomach• HCl starts breaking down foods.• The enzyme pepsin breaks down proteins.• Mucous prevents gastric juices from digesting stomach.• Pyloric sphincter regulates movement offood from stomach to small intestine.



Figure 16.8

Small intestine• Most digestion of carbohydrates, proteins,and fats occurs here.• Nutrients are absorbed into the bloodstream.

Large intestine• Water is reabsorbed


16.2 Organs and Organ Systems - The Digestive System

Villi and microvilli increase the surface area of the intestines to allow nutrient absorption

Figure 16.9

VillusLumen

Mucosal folds

Small intestine One villus Micrograph

Bloodcapillaries

ArterioleVenule

Lymphaticvessel

Microvilli

Nutrients in small intestine



Figure 16.8

Accessory Organs

Liver• Produces bile which aids absorption of fats

Gall bladder• Stores bile and empties into small intestine



Figure 16.8

Accessory Organs

Pancreas• Produces LOTS of digestive enzymes• Produces a bufferthat neutralizes stomach acid• Enzymes & buffer are released into small intestine



An organ system consists of many organs working together

Failure of one organ may compromise the entire system Intestine transplants and pancreatic

transplants are becoming more common Gall bladder and stomach transplants are

rarely done Organ failure can also disrupt multiple

systems



Animation—The Digestive SystemPLAY



Evolution of the Digestive System Paramecia use digestive food vacuoles Hydra have an extracellular digestive sac Earthworms have alimentary canal

Allows for ‘assembly line’ like specialization

Figure 16.9


Homeostasis

Homeostasis a dynamic state of equilibrium in which

internal conditions remain relative stable (Steady State)

homeostasis regulates conditions in the internal environment

A homeostatic control system has a receptor a control center a set point an effector

James M. HutcheonGeorgia Southern University

PowerPoint lecture prepared by


LE 40-11Response

No heatproduced

Roomtemperaturedecreases

Roomtemperature

increases

Set point

Toohot

Set point

Heaterturnedoff

Toocold

Set point

Control center:thermostat

Heaterturnedon

Response

Heatproduced


16.3 Regulating the Internal Environment

Homeostasis Negative feedback is when the outcome

of a process inhibits that process.

Figure 16.11

Pancreassecretes insulin.

Glucose

Liver converts glucoseto glycogen.

Liver breaks down glycogeninto glucose and releasesglucose into bloodstream.

Glycogen

GlucoseGlycogen

Liver

LiverPancreas secretes glucagon.

(a) If blood glucoselevel rises...

Blood glucoselevel falls.

Glucose levels rise.(b) If blood glucoselevel falls...

HomeostasisNormal blood glucose level


16.3 Regulating the Internal Environment

Homeostasis Positive feedback occurs when the outcome of

a process increases or intensifies that process. During childbirth, hormones cause muscles of

uterus to contract Uterine contractions cause even more hormones

to be released, which intensify the contractions

> In animals, regulation is usually by negative feedback because positive feedback often results in amplification – away from homeostasis


16.3 Regulating the Internal Environment –

Organ Donation The best candidates to donate organs are

those who have died of brain injury. In cardiac death, organs deteriorate due to

lack of oxygen, and thus are less suitable for transplant.

Thousands of lives are saved each year through organ donation.

The decision to become a donor now can save families from making difficult decisions later.

copyright 2010 pearson education, inc. chapter 16 tissues, organs, and organ systems organ donation

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