Chapter 21 Unifying Concepts of Animal Structure and

Chapter 21 Unifying Concepts of Animal Structure and Function Power. Point® Lectures for Campbell Essential Biology, Fourth Edition – Eric Simon, Jane Reece, and Jean Dickey Campbell Essential Biology with Physiology, Third Edition – Eric Simon, Jane Reece, and Jean Dickey Lectures by Chris C. Romero, updated by Edward J. Zalisko © 2010 Pearson Education, Inc.

Biology and Society: Keeping Cool • Our bodies are kept in a narrow temperature range. • When we exercise, our bodies are cooled by: – Evaporation of sweat on the skin – Expansion of blood vessels near the skin surface © 2010 Pearson Education, Inc.

Figure 21. 00

• Extreme conditions can lead to: – Loss of consciousness in heat exhaustion – Even higher body temperatures, which can disrupt the brain’s control center – Heat stroke, a life-threatening emergency © 2010 Pearson Education, Inc.

THE STRUCTURAL ORGANIZATION OF ANIMALS • Life is characterized by a hierarchy of organization. • In animals: – Individual cells are grouped into tissues – Tissues combine to form organs – Organs are organized into organ systems – Organ systems make up the entire organism © 2010 Pearson Education, Inc.

Cellular level: Muscle cell Figure 21. 1 -1

Cellular level: Muscle cell Tissue level: Cardiac muscle Figure 21. 1 -2

Cellular level: Muscle cell Tissue level: Cardiac muscle Organ level: Heart Figure 21. 1 -3

Cellular level: Muscle cell Tissue level: Cardiac muscle Organ level: Heart Organ system level: Circulatory system Figure 21. 1 -4

Cellular level: Muscle cell Tissue level: Cardiac muscle Organ level: Heart Organ system level: Circulatory system Organism level: Multiple organ systems functioning together Figure 21. 1 -5

Form Fits Function • Analyzing a biological structure gives us clues about: – What it does – How it works © 2010 Pearson Education, Inc.

(b) At the organ level (a) At the organism level (c) At the cellular level Figure 21. 2

(a) At the organism level Figure 21. 2 a

(b) At the organ level Figure 21. 2 b

(c) At the cellular level Figure 21. 2 c

• Biologists distinguish anatomy from physiology. – Anatomy is the study of the structure of an organism. – Physiology is the study of the function of an organism’s structural equipment. © 2010 Pearson Education, Inc.

Tissues • In most multicellular animals, cells are grouped into tissues. – A tissue is an integrated group of similar cells that perform a specific function. – Animals have four main categories of tissue. © 2010 Pearson Education, Inc.

Epithelial Tissue • Epithelial tissue, also known as epithelium: – Covers the surface of the body – Lines organs and cavities within the body © 2010 Pearson Education, Inc.

Some examples of organs lined with epithelial tissue: Heart Lung Stomach Small intestine Large intestine Urinary bladder Epithelial tissue lining esophagus Epithelial cells Epithelial tissue lining small intestine Figure 21. 3

Some examples of organs lined with epithelial tissue: Heart Lung Stomach Small intestine Large intestine Urinary bladder Figure 21. 3 a

Epithelial tissue lining esophagus Figure 21. 3 b

Epithelial tissue lining small intestine Figure 21. 3 c

• Cells of epithelial tissues: – Are bound tightly together – Form a protective barrier – Fall off and are continuously renewed © 2010 Pearson Education, Inc.

Connective Tissue • Connective tissues have a sparse population of cells in an extracellular matrix consisting of a web of protein fibers within a uniform foundation that may be liquid, jellylike, or solid. • The structure of connective tissue is correlated with its function: to bind and support other tissues. © 2010 Pearson Education, Inc.

Fat droplets Cell Collagen fiber (a) Loose connective tissue (under the skin) (b) Adipose tissue White blood cells Red blood cell Plasma (c) Blood Cell nucleus Collagen fibers Matrix Cells (d) Fibrous connective tissue (forming a tendon) Cells Matrix (f) Bone (e) Cartilage (at the end of a bone) Figure 21. 4

Cell Collagen fiber (a) Loose connective tissue (under the skin) Figure 21. 4 a

Fat droplets (b) Adipose tissue Figure 21. 4 b

White blood cells Red blood cell Plasma (c) Blood Figure 21. 4 c

Cell nucleus Collagen fibers (d) Fibrous connective tissue (forming a tendon) Figure 21. 4 d

Cells Matrix (e) Cartilage (at the end of a bone) Figure 21. 4 e

Matrix Cells (f) Bone Figure 21. 4 f

• Loose connective tissue: – Is the most widespread connective tissue – Binds epithelia to underlying tissues – Holds organs in place © 2010 Pearson Education, Inc.

• Adipose tissue: – Stores fat – Stockpiles energy – Pads and insulates the body © 2010 Pearson Education, Inc.

• Blood: – Is a connective tissue with a matrix of liquid – Contains red and white blood cells suspended in plasma © 2010 Pearson Education, Inc.

• Fibrous connective tissue: – Has a dense matrix of collagen – Forms tendons and ligaments © 2010 Pearson Education, Inc.

• Cartilage: – Has a strong but rubbery matrix – Functions as a flexible, boneless skeleton – Forms the shock-absorbing pads that cushion the vertebrae of the spinal column © 2010 Pearson Education, Inc.

• Bone: – Is a rigid connective tissue – Has a matrix of collagen fibers hardened with deposits of calcium salts © 2010 Pearson Education, Inc.

Muscle Tissue • Muscle tissue: – Consists of bundles of long, thin, cylindrical cells called muscle fibers – Has specialized proteins that contract when stimulated by a nerve © 2010 Pearson Education, Inc.

Unit of muscle contraction Muscle fiber (cell) Muscle Junction between two cells fiber Nucleus Nuclei (a) Skeletal muscle (short segments of several muscle fibers) (b) Cardiac muscle Muscle fiber Nucleus (c) Smooth muscle Figure 21. 5

Unit of muscle contraction Muscle fiber (cell) Nuclei (a) Skeletal muscle (short segments of several muscle fibers) Figure 21. 5 a

Muscle fiber Junction between two cells Nucleus (b) Cardiac muscle Figure 21. 5 b

Muscle fiber Nucleus (c) Smooth muscle Figure 21. 5 c

• Skeletal muscle is: – Attached to bones by tendons – Responsible for voluntary movements – Striated because the contractile apparatus forms a banded pattern in each cell or fiber © 2010 Pearson Education, Inc.

• Cardiac muscle is: – Composed of cells that are branched and striated – Found only in heart tissue – Responsible for the contraction of the heart © 2010 Pearson Education, Inc.

• Smooth muscle is: – Named for its lack of obvious striations – Found in the walls of various organs – Involuntary © 2010 Pearson Education, Inc.

Nervous Tissue • Nervous tissue: – Makes communication of sensory information possible – Is found in the brain and spinal cord – Consists of a network of neurons © 2010 Pearson Education, Inc.

Brain Spinal cord Signal-receiving extensions Cell body LM Signaltransmitting extensions Nerve Figure 21. 6

Brain Spinal cord Nerve Figure 21. 6 a

Cell body Signaltransmitting extensions LM Signal-receiving extensions Figure 21. 6 b

Organs and Organ Systems • An organ consists of two or more tissues packaged into one working unit that performs a specific function. • Examples include the heart, liver, stomach, brain, and lungs. © 2010 Pearson Education, Inc.

Small intestine (cut open) Epithelial tissue Connective tissue (containing blood and lymph vessels) Smooth muscle tissue (two layers) Connective tissue Epithelial tissue Figure 21. 7

Epithelial tissue Connective tissue (containing blood and lymph vessels) Smooth muscle tissue (two layers) Connective tissue Epithelial tissue Figure 21. 7 a

• Organ systems: – Are teams of organs that work together – Perform vital body functions Blast Animation: Anatomy of the Kidney © 2010 Pearson Education, Inc.

Skeletal system: supports body and anchors muscles Bone Cartilage Figure 21. 8 a

Circulatory system: transports substances throughout body Heart Blood vessels Figure 21. 8 b

Nasal cavity Pharynx Larynx Trachea Bronchus Lung Respiratory system: exchanges O 2 and CO 2 between blood and air Figure 21. 8 c

Digestive system: breaks down food and absorbs nutrients Mouth Esophagus Liver Stomach Large intestine Small intestine Anus Figure 21. 8 e

Muscular system: moves body Skeletal muscles Figure 21. 8 d

Urinary system: rids body of certain wastes Kidney Ureter Urinary bladder Urethra Figure 21. 8 f

Hypothalamus Pituitary gland Endocrine system: secretes hormones that regulate body Parathyroid gland Thyroid gland Adrenal gland Pancreas Ovary (female) Testis (male) Figure 21. 8 g

Reproductive system: produces gametes and offspring Seminal vesicles Prostate gland Oviduct Vas deferens Ovary Penis Uterus Urethra Vagina Testis Figure 21. 8 h

Integumentary system: protects body Hair Skin Nail Figure 21. 8 i

Lymphatic and immune system: defends against disease Thymus Spleen Lymph nodes Lymphatic vessels Figure 21. 8 j

Nervous system: processes sensory information and controls responses Brain Sense organ (ear) Spinal cord Nerves Figure 21. 8 k

EXCHANGES WITH THE EXTERNAL ENVIRONMENT • Every organism is an open system, continuously exchanging chemicals and energy with its surroundings to survive. © 2010 Pearson Education, Inc.

• An animal’s size and shape affect how it exchanges energy and materials with its surroundings. • All living cells must be bathed in a watery solution so that exchange of materials can occur. © 2010 Pearson Education, Inc.

• The entire surface area of an amoeba is in contact with the environment. © 2010 Pearson Education, Inc.

Mouth Gastrovascular cavity Exchange (a) Single cell (b) Two cell layers Figure 21. 9

Exchange (a) Single cell Figure 21. 9 a

• A hydra has a body wall only two cell layers thick. • Both layers are bathed in pond water, enabling exchange with the environment. © 2010 Pearson Education, Inc.

Exchange Gastrovascular cavity Exchange (b) Two cell layers Figure 21. 9 b

• Animals with complex body forms face the same basic problems. Every cell must: – Be bathed in fluid – Have access to essential nutrients from the outside environment © 2010 Pearson Education, Inc.

• Complex animals have extensively folded or branched internal surfaces that maximize surface area for exchange with the environment. • Lungs: – Have a very large total surface area – Exchange oxygen and carbon dioxide with the air © 2010 Pearson Education, Inc.

Figure 21. 10

• Animals use three organ systems to exchange materials with the external environment: – Digestive – Respiratory – Urinary • The circulatory system transports materials inside the body from these exchange surfaces. © 2010 Pearson Education, Inc.

Mouth Food CO 2 External environment Animal od o Bl Digestive system Respiratory system Interstitial fluid Heart Nutrients Circulatory system Body cells Urinary system Anus Unabsorbed matter (feces) Metabolic waste products (such as urine) Figure 21. 11

REGULATING THE INTERNAL ENVIRONMENT • Every living organism has the ability to respond to its environment. © 2010 Pearson Education, Inc.

Homeostasis • Homeostasis is the body’s tendency to maintain relatively steady conditions in the internal environment when the external environment changes. • The internal environment of vertebrates is the interstitial fluid, which fills the spaces between cells. © 2010 Pearson Education, Inc.

External environment Animal’s internal environment Homeostatic mechanisms Small internal changes Large external changes Figure 21. 12

Negative and Positive Feedback • Most mechanisms of homeostasis depend on a common principle called negative feedback, in which the results of a process inhibit that same process, such as a thermostat that turns off a heater when room temperature rises to the set point. Animation: Negative Feedback Animation: Positive Feedback © 2010 Pearson Education, Inc.

Response: Heating stops Room temperature drops Thermostat (control center) turns heater off Stimulus: Room temperature is above set point Set point: Room temperature 20 C (68 F) Room temperature rises Stimulus: Room temperature is below set point Response: Heating starts Thermostat (control center) turns heater on Figure 21. 13

Response: Heating stops Room temperature drops Thermostat (control center) turns heater off Stimulus: Room temperature is above set point Set point: Room temperature 20 C (68 F) Figure 21. 13 a

Set point: Room temperature 20 C (68 F) Room temperature rises Stimulus: Room temperature is below set point Response: Heating starts Thermostat (control center) turns heater on Figure 21. 13 b

• Less common is positive feedback in which the results of a process intensify that same process, such as uterine contractions during childbirth. © 2010 Pearson Education, Inc.

Thermoregulation • Thermoregulation is the maintenance of internal body temperature. – Endotherms derive the majority of their body heat from their metabolism. – Ectotherms obtain body heat primarily by absorbing it from their surroundings. © 2010 Pearson Education, Inc.

• Humans have homeostatic mechanisms that aid in thermoregulation, which: – Cool or – Heat the body Blast Animation: Negative Feedback: Body Temperature © 2010 Pearson Education, Inc.

Skin Sweat gland Response: 1. Blood vessels dilate 2. Sweat is produced Control center in brain activates cooling mechanisms Stimulus: Body temperature is above set point Body temperature drops Set point: Body temperature near 37 C (98. 6 F) Body temperature rises Stimulus: Body temperature is below set point Skin Response: 1. Blood vessels constrict 2. Muscles shiver 3. Metabolic rate increases Control center in brain activates warming mechanisms Figure 21. 14

Skin Sweat gland Response: 1. Blood vessels dilate 2. Sweat is produced Control center in brain activates cooling mechanisms Stimulus: Body temperature is above set point Body temperature drops Set point: Body temperature near 37 C (98. 6 F) Figure 21. 14 a

Set point: Body temperature near 37 C (98. 6 F) Body temperature rises Stimulus: Body temperature is below set point Skin Response: 1. Blood vessels constrict 2. Muscles shiver 3. Metabolic rate increases Control center in brain activates warming mechanisms Figure 21. 14 b

• Fever: – Is an abnormally high internal body temperature – Usually indicates an ongoing fight against infection © 2010 Pearson Education, Inc.

The Process of Science: How Does a Python Warm Her Eggs? • Observation: A female Burmese python incubating eggs: – Wraps her body around them – Raises her body temperature – Frequently contracts the muscles in her coils © 2010 Pearson Education, Inc.

• Hypothesis: The muscle contractions elevate the snake’s body temperature. • Experiment: A python and her eggs were monitored to measure: – The python’s muscle contractions – Her oxygen uptake © 2010 Pearson Education, Inc.

• Results: The python’s oxygen consumption increased: – When the temperature in the chamber decreased and – As she increased the rate of muscle contraction. © 2010 Pearson Education, Inc.

O 2 consumption (m. L O 2/hr) per kg 120 100 80 60 40 20 0 5 10 15 20 25 Contractions per minute 30 35 Figure 21. 15

Osmoregulation • Living cells depend on a precise balance of: – Water – Solutes • Osmoregulation is the control of the gain or loss of: – Water – Dissolved solutes, such as salt © 2010 Pearson Education, Inc.

• Osmoconformers: – Have internal and external environments with similar water concentrations – Include most marine invertebrates • Osmoregulators – Actively regulate their water loss or gain – Include freshwater animals, most marine vertebrates, and all land animals © 2010 Pearson Education, Inc.

Osmocomformer Osmoregulator Figure 21. 16

Homeostasis in the Urinary System • The urinary system: – Plays a central role in homeostasis – Forms and excretes urine – Regulates the amount of water and solutes in body fluids © 2010 Pearson Education, Inc.

• In humans, the two kidneys: – Are the main processing centers – Contain many fine tubes called tubules – Include an intricate network of capillaries © 2010 Pearson Education, Inc.

• As blood circulates through the kidneys: – A fraction of it is filtered – Plasma enters the kidney tubules, forming filtrate • Filtrate contains: – Valuable substances that need to be reclaimed (such as water and glucose) – Substances to be eliminated, such as urea © 2010 Pearson Education, Inc.

• The human urinary system includes: – The circulatory system – The kidneys – Nephrons, the functional units of the kidney – The urinary bladder, where urine is stored Animation: Nephron Introduction © 2010 Pearson Education, Inc.

Renal artery (red) and renal vein (blue) Filter Tubule Branch of renal artery Kidney Branch of renal vein Ureter Urinary bladder Collecting duct To ureter (c) A nephron and collecting duct Urethra (a) Urinary system Ureter (b) Kidney Figure 21. 17

Renal artery (red) and renal vein (blue) Kidney Ureter Urinary bladder Urethra (a) Urinary system Figure 21. 17 a

Nephron Ureter (b) Kidney Figure 21. 17 b

• Nephrons: – Carry out the functions of the urinary system – Consist of a tubule and its associated vessels – Number more than a million in a kidney © 2010 Pearson Education, Inc.

Filter Tubule Branch of renal artery Branch of renal vein Collecting duct To ureter (c) A nephron and collecting duct Figure 21. 17 c

• Nephrons perform four key functions: – Filtration, forcing water and other small molecules from the blood to form filtrate – Reabsorption of water and valuable solutes back into the blood – Secretion of certain substances, such as ions and drugs, into the filtrate – Excretion of urine from the kidneys © 2010 Pearson Education, Inc.

Animation: Bowman’s Capsule and Proximal Tubule Animation: Collecting Duct Animation: Effect of ADH Blast Animation: How the Kidney Works Animation: Loop of Henle and Distal Tubule © 2010 Pearson Education, Inc.

Reabsorption Filtration Renal artery Secretion Filtrate Renal vein Capillaries Tubule Excretion Urine Figure 21. 18

• Hormonal control of the nephrons allows the body to control its internal concentration of: – Water – Dissolved molecules © 2010 Pearson Education, Inc.

• Kidney failure can be caused by: – Injury – Illness – Prolonged use of pain relievers, alcohol, or other drugs • One option for treatment of kidney failure is dialysis, filtration of blood by a machine. © 2010 Pearson Education, Inc.

Line from artery to apparatus Pump Line from apparatus to vein Tubing made of a selectively permeable membrane Dialyzing solution Fresh dialyzing Used dialyzing solution (with urea and excess salts) Figure 21. 19

Evolution Connection: Adaptations for Thermoregulation • Animals regulate their body temperatures using adaptations that are: – Anatomical – Physiological, and / or – Behavioral © 2010 Pearson Education, Inc.

METHODS OF THERMOREGULATION Anatomical Adaptations Physiological Adaptations Behavioral Adaptations Fat Hair Panting Bathing Figure 21. 20

Anatomical Adaptations (such as hair, fat, and feathers) Fat Hair Figure 21. 20 a

Physiological Adaptations (such as panting, shivering, and sweating) Panting Figure 21. 20 b

Behavioral Adaptations (such as bathing, basking, hibernating, and migrating) Bathing Figure 21. 20 c

HIERARCHICAL ORGANIZATION OF ANIMALS Level Description Cell The basic unit of all living organisms Tissue Example Muscle cell A collection of similar cells that perform a specific function Cardiac muscle Organ Multiple tissues forming a structure that performs a specific function Heart Organ system A team of organs that work together Circulatory system Organism A living being, which depends on the coordination of all structural levels for homeostasis and survival Person Figure 21. UN 01

HIERARCHICAL ORGANIZATION OF ANIMALS Level Description Cell The basic unit of all living organisms Example Muscle cell Figure 21. UN 01 a

HIERARCHICAL ORGANIZATION OF ANIMALS Level Description Tissue A collection of similar cells that perform a specific function Example Cardiac muscle Figure 21. UN 01 b

HIERARCHICAL ORGANIZATION OF ANIMALS Level Description Organ Multiple tissues forming a structure that performs a specific function Example Heart Figure 21. UN 01 c

HIERARCHICAL ORGANIZATION OF ANIMALS Level Description Organ system A team of organs that work together Example Circulatory system Figure 21. UN 01 d

HIERARCHICAL ORGANIZATION OF ANIMALS Level Description Organism A living being, which depends on the coordination of all structural levels for homeostasis and survival Example Person Figure 21. UN 01 e

Muscle (contracts) Connective (supports organs) Epithelial (covers body surfaces and organs) Nervous (relays and integrates Information) Figure 21. UN 02

External Internal Homeostasis Large changes Small changes within an acceptable range Figure 21. UN 03

Blood Filtration Water and small molecules enter the tubule. Capillary Tubule Reabsorption Water and valuable solutes are returned to the blood. Secretion Specific substances are removed from the blood. Urine Excretion Urine exits the body. Figure 21. UN 04