Unit VII: Animal Structure and Function, Part I

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Unit VII Animal Structure and Function, Part I

• Animal Nutrition, Circulation and Gas Exchange,
  and Immunity

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Unit Objectives

• Observe how animals adjust to the environment
  over the long term by adaptation due to natural
  selection and over the short term by
  physiological responses.
• How do animals obtain energy from the
  environment?
• How do animals obtain O2 for cell
  respiration while disposing of the waste gas CO2?
• How do animals respond to pathogens?

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Epithelial Tissue

• The Cell
• basic unit of structural organization
• for all living things
• tissue (Latin, weave)
• - groups of cells with a
• common structure and
• function
• Epithelial Tissue
• surface tissue- covers every
• surface of the body
• - squamous
• - cuboidal
• - columnar

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Connective Tissue
Live cells in a non-living matrix
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Connective Tissue (cont)

• Blood
• RBC/WBC in water based fluid plasma
• Bone
• osteocytes living in calcified hard matrix
• Ligaments
• fibroblasts in a matrix of collagen fibers
• bone-to-bone connection
• Tendons
• fibroblasts in a matrix of less elastic fibers
• muscle-to-bone connection
• Cartilage
• chondrocytes in a soft/pliable matrix
• Adipose tissue
• mostly cells (little matrix)
• Loose connective tissue
• tissue glue of the body

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Muscle Tissue

• Muscle Tissue
• muscle fibers capable of
• contracting when stimulated
• by nerve impulses
• Skeletal Muscle
• - striated (striped)
• - voluntary movements
• - multinucleated
• Smooth Muscle
• - branched, tapered
• - involuntary actions
• Cardiac Muscle
• - striated, branched
• - no neurons

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Muscle Contraction

• Skeletal Muscle
• two kinds
• fast-twitch (white meat)
• - tend to go anaerobic
• slow-twitch (dark meat)
• - myoglobin-rich
• twitch
• contraction of protein filaments causes
• muscles to shorten
• - thin (actin) and thick (myosin) bands
• - interleaved with each other
• myosin grabs actin and pulls
• - sliding filament theory of muscle
• contraction

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Muscle Contraction

• Sliding Filament Theory
• relaxed muscle
• length of each sarcomere is greater
• - Z-line to Z-line
• Contracting Muscle
• actin/myosin slide past each other
• - shortening the sarcomere
• Contracted Muscle (maximum)
• actin filaments overlap each other
• - sarcomere is very short

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Nervous Tissue
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Organ Systems

• Digestive System mouth anus
• Circulatory System heart, blood vessels,
  blood
• Respiratory System lungs, trachea, other
  breathing tubes
• Immune and Lymphatic System marrow, lymph
  nodes, spleen, WBC
• Excretory System kidneys, ureters, bladder,
  urethra
• Endocrine System hormone-secreting glands
• Reproductive System ovaries, testes, etc.
• Nervous System brain, spinal cord, nerves
• Integumentary System skin and its derivatives
• Skeletal System bones, tendons, ligaments,
  cartilage
• Muscular System skeletal muscles

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Bioenergetics

• Overview
• animals derive chemical energy from
• the environment in food
• digestion breaks down food into
• nutrient molecules
• some energy returns to
• environment as feces
• nutrient molecules enter body cells
• convert to useful form (ATP)
• use ATP for cellular work and
• biosynthesis
• some energy lost as heat
• metabolic rate
• amount of energy an animal uses
• in a unit of time
• BMR

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Energy Content of Food

• Calorimeter
• instrument used to measure the amount
• of energy in a food sample
• food sample is burned, and the
• heat produced is measured
• calorie
• unit commonly used in measuring
• energy content of food
• - amount of heat that is needed
• to raise the temperature of 1 gram
• of water 1ºC
• 1 calorie 4.2 joules
• 1 Calorie kilocalorie (1000 calories)

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Regulating the Internal Environment

• Homeostasis
• the process of controlled and regulating the
  internal environment
• interstitial fluid

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Homeostasis

• Feedback Mechanisms
• negative/positive
• receptors detect a change
• in a variable
• - response depends on the
• type of change
• thermometer (receptor)
• variable (room temperature)
• response (heat produced)

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Human Digestive System

• Alimentary Canal
• tube-within-a-tube
• mouth
• pharynx
• esophagus
• stomach
• small intestine
• large intestine
• rectum
• anus
• 27 feet long!!!
• Take the tour!
• accessory organs
• salivary glands
• liver
• pancreas

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Mouth and Pharynx

• Mechanical Digestion
• teeth and tongue
• Chemical Digestion
• salivary glands
• two types
• - thin, watery
• - thick, mucous
• salivary amylase
• - digests starch
• Swallowing Reflex
• tongue pushes bolus to
• pharynx
• epiglottis closes off
• trachea

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Esophagus

• Peristalsis
• alternate waves of relaxation and contraction
• moves food through alimentary canal
• sphincter
• ring of muscle
• - cardiac sphincter
• - pyloric sphincter

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The Stomach

• Thick-walled, muscular sac
• bolus is stored temporarily
• 2 liters of food/liquid
• 20 minutes or less
• mechanical breakdown
• churning and contracting
• chemical digestion of proteins
• gastric juices
• - hydrochloric acid (ulcers)
• - pepsin
• bolus changed into chyme
• thin, soup liquid

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The Small Intestine

• Small Intestine
• 6.5 meters long,
• 2.5 centimeters diameter
• coiled, folded
• lined with villi
• three regions
• duodenum, jejunum,
• ileum
• site of chemical digestion
• and absorption
• pancreatic juice
• - amylase, protease,
• trypsin, lipase
• bile
• intestinal juice
• - peptidase, maltase

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Stomach Secretions
How does our body know when to secrete these
enzymes? Feedback Mechanisms
Intestinal Secretions
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Large Intestine

• Large Intestine
• 1.5 meters long, 6 centimeters diameter
• four regions
• ascending, transverse, descending,
• and sigmoid colon
• three functions
• reabsorption of water
• - diarrhea/constipation
• absorption of vitamins from bacteria
• - E. coli bacteria produce vit. K
• elimination of feces
• appendix
• vestigial structure with no function

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Circulation and Gas Exchange

• Transport Systems
• functionally connect the organs
• of exchange with the body cells
• diffusion alone is not
• adequate
• circulatory system solves
• this problem
• - chemicals are
• transported b/n the blood
• and interstitial fluid
• O2/CO2,
• nutrients/waste

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Open and Closed Circulatory Systems
animals having many layers of cells - open no
distinction b/n blood and interstitial fluid
hemolymph - closed blood is confined to
vessels and is distinct from interstitial
fluid
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Vertebrate Circulatory System

• Cardiovascular System
• heart, blood vessels, and blood
• heart
• - atria (1 or 2) and
• (1 or 2) ventricles
• blood vessels
• - arteries/arterioles carry blood away from
  the heart
• - veins/venules
• carry blood towards the heart
• - capillaries microscopic vessels with very
  thin, porous walls
• capillary beds networks of capillaries
  infiltrating tissue

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Single circuit flow in fish blood must pass
through two capillary beds Double circuit flow
in amphibian blood is pumped through two
circuits Double circuit flow in mammals
O2-rich blood segregated from O2-poor
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The Mammalian Heart

• Atria
• thin-walled collection chamber
• Ventricles
• thick-walled pumping chamber
• Heart Valves
• atrioventricular (AV) valve
• b/n each atria/ventricle
• - tricuspid/bicuspid
• semilunar valves
• at the each exit of heart

• The LEFT side of the heart services O2-rich blood
  only
• pumps blood through systemic circulation
• The RIGHT side of the heart services O2-poor
  blood only
• pumps blood through pulmonary circulation

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(1) Right Ventricle semilunar valve (2)
Pulmonary arteries right/left (3) Lungs
(Pulmonary Circulation) pulmonary
veins (4) Left Atrium bicuspid valve (5)
Left Ventricle semilunar valve (6)
Aorta (7) Systemic Circulation
head/forelimbs (8) Systemic Circulation
abdominal organs/legs (9) Anterior Vena
Cava (10) Posterior Vena Cava (11) Right
Atrium tricuspid valve
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The Cardiac Cycle

• Lub-dup
• caused by the closing of valves
• lub AV valves
• dup semilunar valves
• - heart murmur
• Pulse
• rhythmic stretching of the
• arteries caused by the
• pressure of blood driven by
• hearts contractions
• heart rate
• - cardiac cycle
• systole/diastole

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The Cardiac Cycle (cont)

• Sinoatrial (SA) node
• specialized muscle tissue that sets the rate at
  which all cardiac
• muscle cells contract
• atrioventricular (AV) node
• - relay point delayed for about 0.1 sec.
• electrocardiogram (ECG/EKG)

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Structure of Blood Vessels

• Arteries and Veins and Capillaries
• arteries thick layer of smooth muscle and
  elastic connective tissue
• carry blood AWAY from the heart
• veins thin layer of smooth muscle
• valves promote unidirectional flow of
  blood
• - varicose veins
• capillaries
• site of exchange only epithelial tissue
• - thin-walled 1 RBC pass through at a
  time
• blood pressure
• blood travels 1000x faster in the aorta
  than the capillaries
• - law of continuity if a pipes diameter
  changes over its
• length, a fluid will stream through narrower
  segments of
• the pipe faster than the wider segments
• but, with so many capillaries

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• Blood Pressure
• Systolic/diastolic
• measured in mm of mercury
• - sphygmomanometer
• systolic pressure created
• when ventricles contract
• diastolic pressure is the
• background pressure
• - blood is constantly under
• some pressure in a
• closed circulatory system

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Lymphatic System

• Lymph
• plasma leaks out of capillaries
• some of it reabsorbed by blood vessels
  (veins)
• - bodys drainage system
• lead back to vena cava through network
  similar to veins
• WBC fight infection
• filaria infection

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Blood

• Components of Blood
• Plasma (55)
• water (91)
• dissolved ions,hormones,
• proteins, nutrients
• - fibrinogen, albumin,
• prothrombin, globulin
• RBC
• erythrocytes (no nucleus)
• - transport O2/CO2
• WBC
• leukocytes
• - defense/immunity
• Platelets
• thrombocytes
• - blood clotting

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• Stem Cells
• bone marrow or embryo
• stem cell research
• luekemia

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Blood Clotting
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Red Blood Cells

• Hemoglobin
• 2.8 x 108 per RBC
• each hemoglobin can carry 4 O2
• uptake of O2 affected by pH
• CO2 combines with H2O in plasma
• - carbonic acid (H2CO3)
• muscles produce a lot of CO2
• - pH around muscles is low (acid)
• lower pH causes hemoglobin to let
• go of O2
• Why do we need to carry these gases?

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Respiratory System

• Gas Exchange
• acquire O2, dispose CO2
• cell respiration
• - uses O2,
• produces CO2
• respiratory medium
• source of O2
• - water vs. air
• respiratory surface
• where O2/CO2 exchange
• takes place
• - must be moist
• earthworm uses skin
• - high ratio of surface
• area to volume

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• Gills
• outfoldings of the body
• surface specialized for gas
• exchange for aquatic animals
• countercurrent exchange
• blood flows in opposite
• direction of water
• - creates diffusion
• gradient

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Tracheal Systems

• Tracheal Systems
• respiratory adaptations for
• terrestrial animals
• air tubes that branch through-
• out the body
• - extend to the surface of nearly every cell

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Lungs

• Respiratory System
• nasal passages
• filtered by hair
• through pharynx to trachea
• rings of cartilage
• larynx (voice box)
• trachea branches into two bronchi
• bronchi branch into many bronchioles
• bronchioles branch into bronchial tubes
• bronchial tubes end in alveoli
• clusters of air sacs
• - surrounded by blood vessels
• - moist, thin-walled

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Ventilating the Lungs

• Breathing
• alternate inhalation and
• exhalation of air
• negative pressure
• - suction pump
• inhalation
• diaphragm pulls
• downward
• rib cage and muscles
• pull upward
• - increases lung volume
• - decrease pressure in lungs
• - fresh air rushes in
• exhalation
• diaphragm/rib cage and muscles relax
• - decreases lung volume
• - air rushes out

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Automatic Control of Breathing

• Breathing Control Centers
• medulla oblongata and pons
• sets basic breathing rhythm
• monitors CO2 levels in blood
• pH of blood
• - drop in pH, increase
• the rate/depth
• O2 sensors in aorta and carotid
• arteries
• sense severely depressed
• levels of O2 (high altitude)
• hyperventilating
• depletes CO2 and fools the
• brain/body into thinking it
• does not need to breath

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Transport of Gases

• Respiratory Pigments
• hemoglobin
• four polypeptide subunits each with
• a cofactor called a heme group
• - iron atom at center of group
• binds to gases reversibly
• - most O2 carried by hemoglobin
• loading and unloading dependent
• on partial pressure of gases
• - gases diffuse from a region of
• higher partial pressure to a
• region of lower partial pressure

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Carbon Dioxide Transport
CO2 Transport 1. CO2 produced by tissues 2.
CO2 diffuses into interstitial fluid and
plasma 3. gt90 enters RBC 4. 23 binds to
hemoglobin 5. Most reacts with H2O to
form H2CO3 6. H2CO3 dissociates into
HCO3- H 7. Hemoglobin takes away H 8.
HCO3- diffuses into plasma 9. Carried to
lungs 10-13. Opposite happens
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The Bodys Defenses

• Nonspecific defense mechanisms
• not selective in their response
• fight off everything the same way
• Specific Defense Mechanisms
• Immune System
• generates efficient and selective response

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Nonspecific Defenses Against Infection

• 1st Line of Defense
• physical and chemical barriers
• skin and mucous membrane
• acid and lysozyme
• 2nd Line of Defense
• phagocytosis
• ingestion of invading organisms by
  certain types of WBC
• - neutrophils and monocytes
• - eosinophils and natural killer (NK) cells
• antimicrobial proteins
• complement system
• - serum proteins help to destroy (lyse)
  microbial cells
• interferons
• - secreted by virus-infected cells
• limit cell-to-cell spread of viral
  infection

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• inflammatory response
• localized response to tissue damage (cut)
  or entry of microorganism
• - increased blood supply (redness/swelling/warmt
  h)
• - histamine and prostaglandins
• aid in delivering clotting elements and
  phagocytic cells

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Specific Immunity

• Immune System Response
• lymphocytes
• B cells and T cells
• - come from stem cells in bone marrow
• mature in different locations before
  moving on to
• lymphoid tissue (lymph nodes, spleen,
  blood, lymph)
• - respond to specific antigens
• clonal selection
• - effector cells and memory cells
• primary and secondary immune response
• self vs. non-self
• autoimmune diseases
• - Type I diabetes, Multiple sclerosis

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Cell-Mediated Immune Response

• T cells
• kill cells that have been infected, or
  parasites
• response initiated through contact with cell or
  macrophage
• divides into four cell lines
• - T memory cells
• - cytotoxic killer T cells
• - T4 helper cells
• core of immune system infected by HIV
• messenger
• - T suppressor cells
• protect our own tissues

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Humoral Immune Response

• B cells
• fights infections of plasma (generally
  bacteria)
• antibody-mediated response
• antibody is quaternary protein (multiple
  polypeptide chains)
• - Y-shaped
• - can bind to variety of antigens
• response to foreign antigen
• - divides into two different cell lines
• memory cells
• plasma cell
• - antibody factory
• - makes antigens easier to locate by
  phagocytes