Chapter 40: Basic Principles of Animal Form

1
Chapter 40 Basic Principles of Animal Form
Function

• Cell size limited by
• surface area volume
• Cells must be in aqueous solution for nutrient
  waste exchange

2
tissues

• Groups of cells with common structure function
• Types
• Epithelial
• Cover body, line organs, body cavities
• Tightly packed held together by tight junctions
• Barrier against microbes, fluid loss, or
  mechanical injury
• Categorized by numbers of layers shape
• Shape
• Cuboidal- dice-like
• Columnar- brick-like
• Squamous- floor tile-like
• Types
• Simple epithelium
• Single layer
• leaky- allows for diffusion
• Ex. Alveoli, capillaries
• Stratified epithelium
• Multiple tiers of cells
• Glandular epithelia

3
(No Transcript)
4

• Connective tissue
• Bind to support other tissues
• Sparse number of cells scattered through an
  extra-cellular matrix
• Consist of 3 protein fibers
• Collagen non-elastic strength resists
  stretching
• Elastin rubbery retain shape
• Reticular branched to connect adjacent tissues

5

• Types of connective tissue
• Loose connective
• Fibroblasts- secrete proteins of extracellular
  fibers
• Macrophages- immune response
• Adipose
• Storage of fat
• For energy insulation
• Fibrous connective
• Tendons- attach muscle to bone
• Ligaments- attach bone to bone
• Cartilage
• Part of all of skeleton in vertebrates
• Bone
• Mineralized connective tissue
• Blood
• Plasma- liquid matrix of water, salts, proteins
• Leukocytes- white blood cells
• Erythrocytes- red blood cells
• Platelets- blood clotting

6
(No Transcript)
7

• Nervous tissue
• Sense stimuli transmit signals within the
  animal
• Neuronnerve cell specialized to conduct impulses
• dendrites extensions that conduct impulses to
  the cell body
• Axons extensions that transmit impulses away
  from the cell body
• Muscle tissue
• Capable of contraction when stimulated
• Consists of contractile proteins actin myosin
• Types
• Skeletal muscle
• Attached to bone by tendons
• Voluntary
• Striated pattern
• Cardiac muscle
• Contractile walls of heart
• Striated pattern
• Smooth muscle
• Lines walls of internal organs
• Involuntary

8
(No Transcript)
9
Organ systems

• Are inter-dependant organs with separate
  functions act in coordinated manner
• Tissues organized into organs except in simple
  organisms
• Some organs are layered (ex. Vertebrate stomach)
• Mesenterysheets of connective tissue in which
  organs are suspended

10
Bioenergetics

• Flow of energy through an organism
• Limits animals behavior, growth, reproduction
• Determines food requirements

11

• Animals are heterotrophs
• Energy Input
• (ingested food)
• Digestion
• (enzymatic hydrolysis of food)
• Absorption
• (small energy molecules by body cells)
• Catabolism
• (cellular respiration fermentation harvest
  chemical energy from food molecules)
• some Energy Stored in ATP some Energy Lost as
  heat is to surroundings
• Energy Used - chemical energy of ATP powers
  cellular work.
• After the needs of staying alive are met,
  leftover chemical
• energy and carbon skeletons from food molecules
  can be
• used in biosynthesis.
• Energy Lost - cellular work generates heat, which
  is lost to surroundings or used to maintain body
  temperature (endotherms)

12
Metabolic rate

• Total amount of energy an animal uses to stay
  alive
• Measured in Calories (kilocalories)
• Calculated by measuring
• oxygen used
• Amount of heat loss per unit of time
• Heat loss is by-product of cellular work
• Heat loss is measured with calorimeter
• Range of metabolic rates
• Minimal rate for life support (breathing,
  sleeping.)
• Maximal rates occur during peak activity (all out
  exercise)
• Vary depending on
• Age, sex, size
• Body and environmental temperature
• Food quality quantity
• Amount of available oxygen
• Hormonal balance
• Time of day activity level

13
Endotherms

• Animals that generate their own body heat
  metabolically
• Includes birds, mammals
• Many endotherms are homeothermic
• Maintain temperature within narrow limits
• Basal metabolic rate
• Endothermic animals metabolic rate measured
  under resting, fasting, stress-free conditions
• Average BMR for humans
• Males.1600-1800 kcal/day
• Females.1300-1500 kcal/day

14
Ectotherms

• Animals that acquire most of their body heat from
  the environment
• Includes fish, amphibian, reptiles,
  invertebrates
• Minimal metabolic rate must be determined at a
  specific temperature
• Standard metabolic rate (SMR)
• Ectotherms minimal metabolic rate measured under
  controlled temperature as well as resting,
  fasting, stress-free conditions

15

• Metabolic rate/gram is inversely related to body
  size among similar animals
• Smaller animals consume more calories/gram than
  larger animals
• Correlated to higher metabolic rate need for
  faster oxygen delivery to tissues
• Small animals have a higher
• Breathing rate
• Blood volume
• Heart rate
• Inverse relationship holds true for both
  endotherms ectotherms

16
Body plans the external environment

• single celled organisms
• must have sufficient surface area of plasma
  membrane to service the entire volume of
  cytoplasm
• Multi-cellular animals body plan
• two-layered sac ... e.g. coelenterates /
  cnideria
• flat-shaped body ... max. surface area exposed
  to water (e.g. the flat worms)
• most complex animals have a small SA volume and
  lack adequate exchange area on the outer surface
  but..
• Highly folded, moist, internal surfaces for
  material exchange.
• Circulatory system shuttles materials between the
  inner outer surfaces

17
Regulating the internal environment

• Mechanisms
• interstitial fluid
• Regulators
• Internal controls used to maintain homeostasis if
  external environment changes
• Conformers
• internal conditions vary with external
  environmental changes
• animal may be regulate according to 1 variable
  conform to another
• Homeostasis depends on feedback circuits (i.e.
  nervous system)
• receptors - detects internal change
• control center - processes information from
  receptors directs the effectors to respond
• effector provides a response

18

• feedback (common method of regulation in animals)
  
• positive feedback
• enhancement of a response
• Rare
• Ex. Blood clotting, childbirth contractions
• negative feedback
• reduced response
• examples insulin regulation in mammal, body
  temp. regulation
• hypothalamus ... detects high blood temperature
  ?impulse to sweat gland ?sweat gland increases
  output ?evaporative cooling ?normal temperature
  obtained? stops sending impulse

19
Thermo-regulators

• Animal maintains internal temperature within a
  tolerable range
• Can be ectotherm or endotherm
• Poikilotherm
• Internal temps vary widely
• Homeotherm
• Relatively stable internal temps
• Modes of heat exchange between organism the
  environment
• Conduction
• Convection
• Radiation
• Evaporation

20
Adaptations for thermo-regulation

• Insulation
• Hair, feathers, fat layers
• Reduce flow of heat between organism the
  environment
• Circulatory adaptations
• Vaso-dilation
• Increase diameter of surface blood vessels
• Warms skin transfers heat to environment by
  radiation, convection, conduction
• Vasoconstriction
• Decreases diameter of surface blood cells
• Reduces blood flow to the surface
• Retain heat
• Countercurrent heat exchange
• Arrangement of blood vessels to help trap heat in
  body core
• Reduces heat loss

21

• Cooling by evaporative heat loss
• Sweating
• Breathing
• Panting
• Increase mucus production
• Spread of saliva on body surface
• Behavioral responses
• Move between shaded sunny locales
• Huddling
• Shivering
• Torpor
• Hibernation- long term (cold)
• Estivation/summer torpor- slow in summer to
  survive high temps low water levels
• Daily torpor- based on feeding times

22

• Acclimatization
• Physiological response occurring over days or
  weeks to environmental temperature change
• Occurs by
• Increasing or decreasing insulation (fur or fat)
• Changing functional enzymes
• Changing proportions of unsaturated fats
  cholesterol in the cell membrane
• Rapid adjustments to temperature change involve
  stress-induced proteins
• i.e. heat shock proteins- protect other proteins
  from denaturization at high temperatures