Chapter 40-44– Animal Structure

and Function

Ch. 40 Key conceptsCh. 40 Key concepts Levels of Organization

– TissueOrganOrgan Systems 4 Types of Tissues

– Epithelial, Connective, Muscle, Nervous Metabolic activity occurs within a whole organism, different tissue

types achieve specialized tasks Homeostasis= stable internal operating conditions Internal body temperature can be maintained in some vertebrates

and depends on a balance between heat produced through metabolism and heat absorbed from or lost to the environment

Major Terms– Anatomy: structure– Physiology: function

Tissues: groups of cells with a common structure and function (4 types)

Tissues: groups of cells with a common structure and function (4 types)

Epithelial: outside of body and lines organs and cavities; held together by tight junctions

Connective: bind and support other tissues

Muscle: capable of contracting when stimulated by nerve impulses

Tissues Types ContinuedTissues Types Continued

Nervous: senses stimuli and transmits signals from 1 part of the animal to another

Neuron: functional unit that transmits impulses

Dendrites: transmit impulses from tips to rest of neuron

Axons: transmit impulses toward another neuron or effector

Organ systemsOrgan systems

Organ: organization of tissues

Mesentaries: suspension of organs (connective tissue)

Thoracic cavity (lungs and heart)

Abdominal cavity (intestines)

Diaphragm (respiration)

Digestive-food processing Circulatory-internal distribution Respiratory-gas exchange Immune/Lymphatic-defense Excretory-waste disposal;

osmoregulation Endocrine-coordination of body activities Reproductive-reproduction Nervous-detection of stimuli Integumentary-protection Skeletal-support; protection Muscular-movement; locomotion

Internal regulationInternal regulation

Interstitial fluid: internal fluid environment of vertebrates; exchanges nutrients and wastes

Homeostasis: “steady state” or internal balance

Negative feedback: change in a physiological variable that is being monitored triggers a response that counteracts the initial fluctuation; i.e., body temp.

Positive feedback: physiological control mechanism in which a change in some variable triggers mechanisms that amplify the change; i.e., uterine contractions at childbirth

Regulation of body temperature• Thermoregulation• 4 physical processes:

– Conduction~transfer of heat between molecules of body and environment

– Convection~transfer of heat as water/air move across body surface

– Radiation~transfer of heat produced by organisms

– Evaporation~loss of heat from liquid to gas

• Sources of body heat:– Ectothermic: determined by

environment– Endothermic: high metabolic rate

generates high body heat

Metabolism: sum of all energy-requiring biochemical reactions

Metabolism: sum of all energy-requiring biochemical reactions

Catabolic processes of cellular respiration

Calorie; kilocalorie/C Endotherms: bodies warmed by

metabolic heat Ectotherms: bodies warmed by

environment Basal Metabolic Rate (BMR):

minimal rate powering basic functions of life (endotherms)

Standard Metabolic Rate (SMR): minimal rate powering basic functions of life (ectotherms)

Ch. 41: Digestion and Nutrition• Raw materials for building organic molecules are

obtained through ingestion and circulated to cells• Regions of the body are specialized for processing,

transporting, and storing raw materials• Nutrition refers to ingesting, digesting, absorbing,

and releasing organic molecules• Vitamins and minerals are necessary components of

diet that cannot necessarily be produced by the organism on its own

• When metabolic activity and physical exertion are in balance acceptable body weight and overall health are maintained

Nutritional requirements• Undernourishment: caloric

deficiency• Overnourishment (obesity): excessive

food intake• Malnourishment: essential nutrient

deficiency• Essential nutrients: materials that

must be obtained in preassembled form

• Essential amino acids: the 8 amino acids that must be obtained in the diet

• Essential fatty acids: unsaturated fatty acids

• Vitamins: organic coenzymes• Minerals: inorganic cofactors

Overview of food processing• 1-Ingestion: act of eating

• 2-Digestion: process of food break down– enzymatic hydrolysis

• intracellular: breakdown within cells (sponges)

• extracellular: breakdown outside cells (most animals)

– alimentary canals (digestive tract)

• 3- Absorption: cells take up small molecules

• 4- Elimination: removal of undigested material

• Incomplete digestive system– Animals with simple body plans have a

gastrovascular cavity that functions in both digestion and distribution of nutrients

• Complete digestive system– More complex animals have a digestive tube with

two openings, a mouth and an anus– This digestive tube is called a complete digestive

tract or an alimentary canal– It can have specialized regions that carry out

digestion and absorption in a stepwise fashion

Each organ of the mammalian digestive system has specialized food-processing functions

• The mammalian digestive system consists of an alimentary canal and accessory glands that secrete digestive juices through ducts

• Mammalian accessory glands are the salivary glands, the pancreas, the liver, and the gallbladder

• Food is pushed along by peristalsis, rhythmic contractions of muscles in the wall of the canal

Esophagus

Stomach

Liver

Salivaryglands

Gall-bladder

Pancreas

Rectum

Anus

Largeintestines

Smallintestines

Mouth

A schematic diagram of thehuman digestive system

The Oral Cavity, Pharynx, and Esophagus

• In the oral cavity:– food is lubricated and digestion begins

– Teeth chew food into smaller particles that are exposed to salivary amylase, initiating breakdown of glucose polymers

• The region we call our throat is the pharynx, a junction that opens to both the esophagus and the windpipe (trachea)

• The esophagus conducts food from the pharynx down to the stomach by peristalsis

Epiglottisup

Bolus of food

Esophagealsphinctercontracted

Esophagus

To stomachTo lungs

Trachea

Tongue

Pharynx

Glottis

Larynx

Esophagealsphincterrelaxed

Epiglottisdown

Glottis upand closed

Epiglottisup

Esophagealsphinctercontracted

Relaxedmuscles

Glottis downand open

Relaxedmuscles

Contractedmuscles

Stomach

The Stomach• The stomach stores food and secretes gastric juice,

which converts a meal to acid chyme• Gastric juice is made up of hydrochloric acid and the

enzyme pepsin• Mucus protects the stomach lining from gastric juice

Esophagus

Cardiac orifice

Pyloric sphincter

Smallintestine Folds of

epithelialtissue

Stomach

Epithelium

Pepsin(active enzyme)

Pepsinogen

HCl

Pepsinogen and HClare secreted into the lumen of the stomach.

HCl convertspepsinogen to pepsin.

Pepsin then activatesmore pepsinogen,starting a chainreaction. Pepsinbegins the chemicaldigestion of proteins.

Parietal cellChief cell

Chief cells

Mucus cells

Parietal cells

Interior surface of stomach

Gastric gland

5 µ

m

The Small Intestine

• The small intestine is the longest section of the alimentary canal

• It is the major organ of digestion and nutrient absorption

• Enzymatic Action in the Small Intestine– The first portion of the small intestine is the duodenum,

where acid chyme from the stomach mixes with digestive juices from the pancreas, liver, gallbladder, and the small intestine itself

Stomach

Pancreas

Liver

Gall-bladder

Duodenum ofsmall intestine

Intestinaljuice

Bile

Acid chyme

Pancreatic juice

• The pancreas produces proteases, protein-digesting enzymes that are activated after entering the duodenum

• The liver produces bile, which aids in digestion and absorption of fats

• Enzymatic digestion is completed as peristalsis moves the chyme and digestive juices along the small intestine

Absorption of Nutrients

• The small intestine has a huge surface area, due to villi and microvilli that are exposed to the intestinal lumen

• The enormous microvillar surface greatly increases the rate of nutrient absorption

• Each villus contains a network of blood vessels and a small lymphatic vessel called a lacteal

Key

Nutrientabsorption

Microvilli(brush border)

Epithelial cells

Lacteal

Lymphvessel

Villi

Largecircularfolds

Epithelialcells

Bloodcapillaries

Vein carrying bloodto hepatic portalvessel

Muscle layers

Villi

Intestinal wall

The Large Intestine• The large intestine, or colon, is connected to the small

intestine• Its major function is to recover water that has entered

the alimentary canal• Wastes of the digestive tract, the feces, become more

solid as they move through the colon• Feces pass through the rectum and exit via the anus

Ch. 42 Key ConceptsCh. 42 Key Concepts

Circulation is a system of exchanging materials within the body

Blood is the transport tissue used in circulation The heart is the central organ of circulation in most

animals, it has alternating vessels with oxygenated (arteries) and deoxygenated (veins) blood

Capillaries= diffusion/exchange zones Lymphatic system= delivery system that takes

interstitial fluid to the blood, immune function

Circulation system evolutionCirculation system evolution

Open circulatory – hemolymph (blood &

interstitial fluid) – sinuses (spaces

surrounding organs) Closed circulatory: blood

confined to vessels Cardiovascular system

– heart (atria/ventricles) – blood vessels (arteries,

arterioles, capillary beds, venules, veins)

– blood (circulatory fluid)

Blood vessel structural differencesBlood vessel structural differences

Capillaries: exchange points for nutrients, water, gases

Arteries: carry oxygenated blood away from the heart

Veins: return deoxygenated blood to the heart

Double circulationDouble circulation From right ventricle to lungs via

pulmonary arteries through semilunar valve (pulmonary circulation)

Capillary beds in lungs to left atrium via pulmonary veins

Left atrium to left ventricle (through atrioventricular valve) to aorta

Aorta to coronary arteries; then systemic circulation

Back to heart via two venae cavae (superior and inferior); right atrium

The lymphatic systemThe lymphatic system

Lymphatic system: system of vessels and lymph nodes, separate from the circulatory system, that returns fluid and protein to blood

Lymph: colorless fluid, derived from interstitial fluid

Lymph nodes: filter lymph and help attack viruses and bacteria

Body defense / immunity

BloodBlood

Plasma: liquid matrix of blood in which cells are suspended (90% water)

Erythrocytes (RBCs): transport O2 via hemoglobin Leukocytes (WBCs): defense and immunity Platelets: clotting

Respiration• The ATP producing metabolic pathway of cellular

respiration requires oxygen and produces carbon dioxide waste

• Oxygen and carbon dioxide diffuses as a result of pressure gradients between tissue and the surrounding air

• Blood flows to deliver oxygen and carbon dioxide from and to respiratory membranes in the body

• The rate of air flow should match the rate of blood flow and rhythmically match up to breathing rates in animals

Gas exchange occurs across specialized respiratory surfaces

• Gas exchange supplies oxygen for cellular respiration and disposes of carbon dioxide

• Animals require large, moist respiratory surfaces for adequate diffusion of gases between their cells and the respiratory medium, either air or water

Respiratorymedium(air or water)

Organismallevel

Cellular level

Energy-richfuel molecules

from food

Respiratorysurface

Circulatory system

Cellular respiration

CO2O2

ATP

Gas exchange

• CO2 <---> O2

• Aquatic: •gills •countercurrent exchange

• Terrestrial: •tracheal systems •lungs

Mammalian Respiratory Systems: A Closer Look

• A system of branching ducts conveys air to the lungs• Air inhaled through the nostrils passes through the

pharynx into the trachea, bronchi, bronchioles, and dead-end alveoli, where gas exchange occurs

Branchfrompulmonaryvein(oxygen-richblood)

Terminalbronchiole

Branchfrompulmonaryartery(oxygen-poorblood)

Alveoli

50 µ

m

Colorized SEMSEM

Nasalcavity

50 µ

m

Leftlung

Heart

Larynx

Pharynx

EsophagusTrachea

Rightlung

Bronchus

Bronchiole

Diaphragm

Breathing ventilates the lungs

• The process that ventilates the lungs is breathing, the alternate inhalation and exhalation of air

Rib cageexpands asrib musclescontract

Airinhaled

Lung

Diaphragm

INHALATIONDiaphragm contracts

(moves down)

Rib cage getssmaller asrib musclesrelax

Airexhaled

EXHALATIONDiaphragm relaxes

(moves up)

Mammalian respiratory systems• Larynx (upper part of

respiratory tract)

• Vocal cords (sound production)

• Trachea (windpipe)

• Bronchi (tube to lungs)

• Bronchioles

• Alveoli (air sacs)

• Diaphragm (breathing muscle)

Ch 43: Immunity

• Key Concepts– The vertebrate body has defense mechanisms that

are physical, chemical, and cellular in nature– Generalized response is accomplished through

phagocytosis using white blood cells and plasma proteins

– Antigens can be chemically recognized by antibodies and destroyed by white blood cells

– Natural killer cells destroy abnormal cells

Overview: Reconnaissance, Recognition, and Response

• An animal must defend itself from the many dangerous pathogens it may encounter

• Two major kinds of defense have evolved: innate immunity and acquired immunity

• Innate immunity is present before any exposure to pathogens and is effective from the time of birth

• It involves nonspecific responses to pathogens• Innate immunity consists of external barriers plus

internal cellular and chemical defenses• Key internal defenses are macrophages and other

phagocytic cells

• Acquired immunity, or adaptive immunity, develops after exposure to agents such as microbes, toxins, or other foreign substances

• It involves a very specific response to pathogens• Recognition is by white blood cells called

lymphocytes• Some lymphocytes produce antibodies; others

destroy infected cells, cancer cells, or foreign tissue

External Defenses• Skin and mucous membranes are physical barriers to

entry of microorganisms and viruses• Mucous membrane cells produce mucus, a viscous

fluid that traps microbes and other particles• In the trachea, ciliated epithelial cells sweep mucus

and any entrapped microbes upward, preventing microbes from entering the lungs

Internal Cellular and Chemical Defenses

• Internal cellular defenses depend mainly on phagocytosis

• White blood cells called phagocytes ingest microorganisms and initiate inflammation– Phagocytes attach to prey via surface receptors

and engulf them, forming a vacuole that fuses with a lysosome

PseudopodiaMicrobes

MACROPHAGE

Lysosomecontainingenzymes

Vacuole

• Macrophages, a type of phagocyte, migrate through the body and are found in organs of the lymphatic system

• The lymphatic system defends against pathogens

Phagocytic and Natural Killer Cells• Neutrophils

– 60-70% WBCs; engulf and destroy microbes at infected tissue

• Macrophages

– enzymatically destroy microbes

• Eosinophils

– 1.5% WBCs; destroy large parasitic invaders (blood flukes)

• Natural killer (NK) cells

– destroy virus-infected body cells & abnormal cells

Inflammatory Response

• In local inflammation, histamine and other chemicals released from injured cells promote changes in blood vessels

• These changes allow more fluid, phagocytes, and antimicrobial proteins to enter tissues

The Inflammatory Response1- Tissue injury; release of chemical signals~

• histamine (mast cells): causes Step 2...

• increases blood flow & vessel permeability

2- Dilation and increased permeability of capillary~

• chemokines: secreted by blood vessel endothelial cells mediates phagocytotic migration of WBCs

3- Phagocytosis of pathogens~

• pyrogens cause fever: leukocyte-released molecules increase body temp.

Specific Immunity• Lymphocyctes

– pluripotent stem cells...• B Cells (bone marrow)• T Cells (thymus)

Specific Immunity• Antigen: a foreign

molecule that elicits a response by lymphocytes (virus, bacteria, fungus, protozoa, parasitic worms)

• Antibodies: antigen-binding immunoglobulin, produced by B cells

• Antigen receptors: plasma membrane receptors on b and T cells

Self/Nonself Recognition• Self-tolerance: capacity to distinguish self from non-self

• Autoimmune diseases: failure of self-tolerance; multiple sclerosis, lupus, rheumatoid arthritis, insulin-dependent diabetes mellitus

• Major Histocompatability Complex (MHC): body cell surface antigens coded by a family of genes

• Class I MHC molecules: found on all nucleated cells

• Class II MHC molecules: found on macrophages, B cells, and activated T cells

• Antigen presentation: process by which an MHC molecule “presents” an intracellular protein to an antigen receptor on a nearby T cell

• Cytotoxic T cells (TC): bind to protein fragments displayed on class I MHC molecules

• Helper T cells (TH): bind to proteins displayed by class II MHC molecules

Induction of Immune Responses• Primary immune response: lymphocyte proliferation and differentiation

the 1st time the body is exposed to an antigen

• Plasma cells: antibody-producing effector B-cells

• Secondary immune response: immune response if the individual is

exposed to the same antigen at some later time~ Immunological memory

Types of immune responses

• Antibody/Humoral immunity– B cell activation– Production of antibodies– Defend against bacteria,

toxins, and viruses free in the lymph and blood plasma

• Cell-mediated immunity– T cell activation– Binds to and/or lyses

cells– Defend against cells

infected with bacteria, viruses, fungi, protozoa, and parasites; nonself interaction

Clonal selection• Effector cells: short-lived cells that

combat the antigen

• Memory cells: long-lived cells that bear receptors for the antigen

• Clonal selection: antigen-driven cloning of lymphocytes

• “Each antigen, by binding to specific receptors, selectively activates a tiny fraction of cells from the body’s diverse pool of lymphocytes; this relatively small number of selected cells gives rise to clones of thousands of cells, all specific for and dedicated to eliminating the antigen.”

Helper T Cells play a central role in acquired immune response.

Ch. 44: Internal Regulation• Animals regulate the intake and exposing of water

and waste• Urinary systems balance water in vertebrates• Kidneys are blood filtering organs with nephron cells• Urine contains materials not returned to the blood

Water balance and waste disposal• Osmoregulation:

– management of the body’s water content and solute composition

• Nitrogenous wastes: breakdown products of proteins and nucleic acids; ammonia-very toxic

• Deamination~– Ammonia: most aquatic animals,

many fish

– Urea: mammals, most amphibians, sharks, bony fish (in liver; combo of NH3 and CO2)

– Uric acid: birds, insects, many reptiles, land snails

Excretory Systems• Production of urine by 2

steps:

– Filtration (nonselective)

– Reabsorption (secretion of solutes)

• Kidneys ~ vertebrates– Renal cortex (outer region)

– Renal medulla (inner region)

– Nephron: functional unit of kidney

• Renal artery/vein: kidney blood flow

• Ureter: urine excretory duct

• Urinary bladder: urine storage

• Urethra: urine elimination tube