Human Biology

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Human Biology

• A study of the anatomy and physiology of human
  body systems

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A. Introduction

• 1. Functional anatomy
• a. Anatomy - study of structure of an organism
• b. Physiology - study of functions an organism
  performs
• c. Cells, tissues, organs, organ systems
• d. Tissues - 4 main categories
• i. Epithelial
• ii. Connective
• iii. Nervous
• iv. Muscle

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• 2. Tissues
• a. Epithelial
• i. Covers outside of body and lines organs and
  cavities
• ii. Tightly packed
• iii. Functions as a barrier
• iv. Types of epithelia
• Simple epithelium - single layer
• Stratified epithelium - multiple tiers
• Shapes of cells
• Cuboidal - dice
• Columnar - bricks
• Squamous - flat

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Epithelial tissue
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• 2. Tissues
• b.Connective
• i. Bind and support other tissues
• ii. Types
• Loose connective tissue - binds epithelia to
  underlying tissue and holds organs in place
• Adipose tissue - stores fat
• Fibrous connecive tissue
• Tendons - muscles to bones
• Ligaments - bone to bone
• Cartilage
• Bone

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• 2. Tissues
• b. Connective
• Blood
• Plasma - liquid portion
• Erythrocytes - red blood cells
• Leukocytes - white blood cells
• Platelets - function in blood clotting
• c. Nervous
• Neuron - nerve cell
• d. Muscle
• Skeletal - voluntary
• Cardiac - heart
• iii. Smooth - involuntary, lining of digestive
  tract

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Connective tissue
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Muscle tissue
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Intro to Animal Form and Function

• 3. Organ systems
• Digestive
• Circulatory
• Respiratory
• Immune
• Excretory
• Endocrine
• Reproductive
• Nervous
• Integumentary
• Skeletal
• Muscular

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• 4. Regulating internal environment
• a. Interstitial fluid - fills spaces between
  cells, exchange
• b. Homeostasis - internal balance
• c. Feedback mechanisms
• a. Negative feedback - prevent small changes
  from becoming too large
• Body temperature control
• b. Positive feedback - amplify changes
• Childbirth

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Regulating internal environment
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• Bioenergetics - flow of energy through an animal
• Metabolic rate - amount of energy an animal uses
  in a unit of time
• Endothermic - warm-blooded
• Ectothermic - cold-blooded
• Metabolic rate is inversely related to body size
• Mouse uses 20 times more calories/gram than an
  elephant
• Higher breathing rate, blood volume, heart rate,
  food consumption
• Surface areavolume

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• Bioenergetics
• Metabolic rates change
• Basal metabolic rate - nongrowing, endotherm at
  rest with an empty stomach and no stress
• Standard metabolic rate - resting, fasting,
  nonstressed ectotherm at a standard temperature

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Metabolic rates
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B. Digestive system

• 1. Feeding mechanisms
• a. Dietary categories
• i. Herbivores
• ii. Carnivores
• iii. Omnivores
• b. Feeding adaptations
• a. Suspension-feeders - sift small food
  particles from water
• b. Substrate-feeders - live in or on food source
• c. Fluid-feeders - suck nutrient rich fluid from
  living host
• d. Bulk-feeders - large pieces of food

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• 2. Food processing - four main stages
• a. Ingestion
• b. Digestion - cleaves macromolecules into
  component monomers
• Polysaccharides into simple sugars
• Fats into glycerol and fatty acids
• Proteins into amino acids
• Nucleic acids into nucleotides
• Enzymatic hydrolysis
• c. Absorption
• d. Elimination

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• 3. Mammalian digestive system (alimentary canal)
• a. Oral cavity
• b. Pharynx
• c. Esophagus
• d. Stomach
• e. Small intestine
• f. Large intestine

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• a. Oral cavity
• i. Mucin - glycoprotein that protects the soft
  lining of the mouth and lubricates food
• ii. Salivary amylase - hydrolyzes starch and
  glycogen
• iii. Bolus
• b. Pharynx
• Epiglottis - cartilaginous flap that blocks the
  glottis
• c. Esophagus
• i. Conducts food from pharynx to stomach
• ii. Peristalsis

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Animal Nutrition

• d. Stomach
• i. Stretch to hold 2 liters of food and fluid
• ii. Gastric juice secreted by epithelium lining
  the stomach wall
• pH of 2 - hydrochloric acid
• Pepsin - enzyme that begins hydrolysis of
  proteins
• Pepsinogen released by chief cells
• Acid released by parietal cells
• Pepsinogen converted to active pepsin when
  exposed to HCl
• iii. Mechanical digestion - smooth muscles churn
  contents of stomach every 20 second
• iv. Acid chyme is produced
• v. Pyloric sphincter regulates passage of chyme
  to intestine

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• e. Small intestine
• i. Duodenum - first 25 cm of small intestine
• Digestive juices from pancreas, liver,
  gallbladder, and gland cells of the intestinal
  wall mix with acid chyme
• Carbohydrate digestion
• Pancreatic amylase breaks down starch, glycogen,
  and smaller polysaccharides into disaccharides
• Protein digestion
• Trypsin and Chymotrypsin break peptide bonds to
  break large polypeptides into shorter chains -
  secreted by pancreas
• Dipeptidases break small peptides
• Carboxypeptidase breaks off one amino acid at a
  time secreted by pancreas
• Aminopeptidase breaks off one amino acid at a
  time - secreted by intestinal epithelium

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• e. Small intestine
• i. Duodenum
• Nucleic acid digestion
• Nucleases
• Nucleotidases
• Nucleosidases
• Fat digestion
• Bile salts secreted by gall bladder to coat fat
  droplets - emulsification
• Lipase hydrolyzes fat molecules
• ii. Jejunum - absorption of nutrients and water
• iii. Ileum - absorption of nutrients and water

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• e. Small intestine
• iv. Absorption of nutrients
• Villi - fingerlike projections in lining of
  intestines
• Microvilli - microscopic appendages on each
  epithelial cell of a villus
• Capillaries

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• f. Large intestine
• i. Otherwise known as the colon
• ii. Major function of large intestine is to
  reclaim water

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Overview of digestion
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Circulatory system

• Variations in circulatory systems
• Gastrovascular cavity - functions in digestion
  and distribution of substances in body
• Open circulatory system
• Blood bathes organs directly
• Hemolymph - blood and interstitial fluid
• Sinuses - spaces surrounding organs
• Closed circulatory system
• Blood confined in vessels, separate from
  interstitial fluid

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Circulatory system

• Adaptations of cardiovascular system
• Structure of heart
• Arteries - carrry blood away from heart
• Branch into arterioles
• Arterioles carry blood to capillaries
• Veins - carry blood toward heart
• Capillaries - vessels with thin, porous walls
  that infiltrate tissues

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Circulatory system

• Fish
• Heart composed of two chambers
• One ventricle
• One atrium
• Arteries
• Gill capillaries
• Systemic capillaries
• Veins

• Amphibians
• Double circulation
• Three-chambered heart
• Two atria
• One ventricle that pumps blood into forked artery
• Pulmocutaneous circulation
• Systemic circulation

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C. Circulatory system
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C. Circulatory system

• 1. Mammalian circulatory system
• Double circulation
• Pulmonary circuit
• Systemic circuit
• b. Four-chambered heart
• i. Two atria
• ii. Two ventricles
• c. Path of blood flow

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• 2. Mammalian heart
• a. Cardiac cycle
• i. Systole - contraction phase
• ii. Diastole - relaxation phase
• b. Cardiac output - volume of blood per minute
  pumped by the left ventricle
• i. Heart rate - number of beats per minute
• ii. Stroke volume - amount of blood pumped by
  left ventricle
• c. Valves prevent backflow and keep blood moving
  in right direction

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• 3. Regulation of heart beat
• a. Sinoatrial (SA) node - generates electrical
  impulse to set the rate and timing at which all
  cardiac muscle cells contract
• b. Atrioventricular (AV) node - located in wall
  between right atrium and right ventricle
• c. Electrocardiogram (ECG or EKG)

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Circulatory system

• Blood pressure
• Systolic pressure
• Diastolic pressure
• Transfer of substances between blood and
  interstitial fluid occurs across thin walls of
  capillaries
• Movement depends on two opposing forces
• Blood pressure
• Osmotic pressure

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Circulatory system

• Lymphatic system
• Returns lost fluid and proteins to blood
• Plays an important role in bodys defense as well
• Components of blood
• Plasma - liquid portion of blood
• Erythrocytes - red blood cells that contain
  hemoglobin
• Leukocytes - white blood cells
• Monocytes
• Neutrophils
• Basophils
• Eosinophils
• Lymphocytes
• Platelets - cell fragments that function in blood
  clotting

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Circulatory system

• Components of blood
• Pluripotent stem cells
• Found in red marrow of bones
• Potential to differentiate into different types
  of cells
• Differentiate into erythrocytes, leukocytes,
  and platelets
• Blood clotting
• Fibrinogen - inactive form of clotting protein
  present in blood
• Fibrin - active clotting protein
• Thrombus - clump of platelets and coagulated
  fibrin that blocks flow of blood

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Circulatory system

• 4. Cardiovascular diseases
• a. Heart attack - death of cardiac muscle tissue
• b. Stroke - death of nervous tissue
• c. Atherosclerosis - plaques develop on the
  inner walls of arteries
• d. Arteriosclerosis - hardening of arteries
• e. Hypertension - high blood pressure

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D. Respiratory system

• 1. Gas exchange in animals
• a. Uptake of oxygen and release of carbon
  dioxide
• b. Respiratory medium - source of oxygen
• c. Respiratory surface
• i. Movement of gases across membranes is based
  on diffusion
• ii. Rate of diffusion is proportional to surface
  area
• iii. Moist membranes
• iv. Larger respiratory surface in endotherms
  than ectotherms

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Respiratory system

• Gills
• Outfolds of body surface suspended in water
• Ventilation - increases the flow of respiratory
  medium over the surface
• Countercurrent exchange - blood flows through
  capillaries in opposite direction of water

• Tracheal systems
• Composed of air tubes that branch throughout the
  body
• Trachea - open to outside

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Respiratory system

• 2. Lungs
• a. Dense net of capillaries under the epithelium
  that forms the respiratory system
• b. Mammalian respiratory systems
• i. Nasal cavity
• ii. Pharynx
• iii. Larynx
• iv. Trachea - supported by rings of cartilage
• v. Bronchi
• vi. Bronchioles
• vii. Alveoli

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Respiratory system

• 2. Lungs
• c. Ventilating the lungs
• i. Negative pressure breathing - mammals
• Diaphragm - expands the rib cage by pulling ribs
  upward and the breastbone outward
• As lung volume increases, air pressure in alveoli
  becomes lower than atmospheric pressure
• Air rushes through nostrils to the alveoli
• ii. Tidal volume - volume of air an animal
  inhales and exhales with each breath
• iii. Vital capacity - maximum tidal volume
  during forced breathing
• iv. Residual volume - air that remains in lungs
  after forceful exhalation

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Respiratory system

• 3. Respiratory pigments
• a. Proteins that transport oxygen
• b. Hemoglobin
• i. Contained in red blood cells
• ii. Consists of four subunits
• Each contains a heme group that contains iron
• iii. Iron binds to oxygen
• iv. Also helps to transport carbon dioxide
• c. Myoglobin - found in diving mammals

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E. Excretory System

• Animals must dispose of nitrogenous wastes
• Wastes result from breakdown of proteins and
  nucleic acids
• Types of nitrogenous wastes
• Ammonia in aquatic animals
• Urea in mammals, most amphibians, and some fishes
• - Liver functions in production of urea
• Uric acid in birds and reptiles

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Excretory System
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Excretory System

• Human excretory system
• Kidney - filters blood
• Ureter - carries waste to bladder
• Urinary bladder - stores waste
• Urethra - carries waste out of body
• Blood circulation
• Renal artery - carries blood to kidney
• Renal vein - carries blood to heart from kidney

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Human Excretory System
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Human Excretory System

• Kidney structure and function
• Nephron - functional unit of a kidney
• Bowmans capsule - blood filtering unit
  containing ball of capillaries (glomerulus)
• Proximal tubule - reabsorbs nutrients, salt, and
  water back into blood
• Loop of Henle - water reabsorption
• Distal tubule - reabsorbs salt and water back
  into blood
• Collecting duct - reabsorbs salt and water back
  into blood
• Antidiuretic hormone (ADH) increases water
  reabsorption from the kidney

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Nephron function
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Dialysis treatment
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F. Nervous System

• Main divisions of the nervous system
• Central nervous system
• Consists of brain and the spinal cord
• Organizes information and orders the body to
  respond to its environment in a way that
  maintains homeostasis
• Peripheral nervous system
• Consists of motor and sensory neurons
• Monitors the body and environment and carries
  instructions from the central nervous system

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Nervous System
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Nervous System

• Functions
• Sensory input
• Sensory neurons
• Conveys signal from sensory receptors into CNS
• Integration
• Interneurons
• Integrate data and relay signals
• Motor output
• Motor neurons
• Convey signal from CNS to effector cells

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Nervous System

• Neuron structure
• Cell body - includes organelles and nucleus
• Dendrites - receive signals from other neurons
• Axon - transmits signals to other cells
• Myelin sheath - insulating material surrounding
  axon
• Synaptic terminal - end of neuron where
  information is passed to another neuron or
  effector cell

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Nervous System

• Neuron function
• Nerve signals are based on electric charge
• Changes in electric charge difference across the
  neuron membrane result in an action potential,
  otherwise known as a nerve signal
• Change in electric charge results from movement
  of sodium and potassium ions across the membrane
• Opening of ion channels usually results from
  release of neurotransmitters at the synapse
• Neurotransmitter - chemical messenger that
  carries information from transmitting neuron to a
  receiving cell
• Synapse - junction between a neuron and another
  neuron/effector cell

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Nervous System
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Nervous System

• Examples of neurotransmitters
• Acetylcholine - functions in brain and at
  synapses between motor neurons and muscle cells
• Biogenic amines - important in CNS
• Examples include epinephrine, norepinephrine,
  serotonin, and dopamine
• Parkinsons - lack of dopamine in brain
• Many drugs alter the effects of neurotransmitters

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Nervous System

• Divisions of Peripheral Nervous System (PNS)
• Somatic - voluntary control
• Autonomic - involuntary control
• Parasympathetic - gain and conserve energy
• Sympathetic - energy-consuming activities
• Enteric - functions in digestion

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Nervous System
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Skeletal System

• Axial skeleton
• Skull
• Vertebral column
• Rib cage
• Appendicular skeleton
• Bones of appendages
• Bones that anchor appendages to axial skeleton

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Skeletal System

• Joints provide versatility to human skeleton
• Ligaments - hold together bones of joints
• Types of joints
• Ball-and-socket - rotation of arms and legs,
  movement in several planes
• Hinge - movement in single plane
• Pivot - rotation of forearm at elbow

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Skeletal System

• Bone function
• Protection - skull and rib cage
• Movement
• Mineral storage
• Marrow produces blood cells and stores fat
• Bone structure
• Minerals - Ca, P, Mg, Mn
• Bone marrow
• Yellow - stores fat
• Red - produces blood cells
• Cartilage at ends

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Interaction between skeleton and muscle
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H. Muscular System

• Skeleton and muscles interact in movement
• Tendons - connect muscles to bones
• Movement of bones in opposite directions requires
  antagonistic pairs of muscles

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Muscular System

• Muscle structure
• Muscle fibers - individual cells that occur in
  bundles
• Myofibrils - contractile threads in fibers
• Sarcomere - contractile apparatus in myofibril
• Thin filaments composed of the protein actin
• Thick filaments composed of the protein myosin
• Sarcomere contracts (shortens) when thin
  filaments slide across thick filaments

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Muscular System

• Sliding filament model of muscle contraction
• Myosin attaches to an actin binding site
• Actin thin filaments slide towards the center of
  the sarcomere
• Sarcomere shortens
• Requires ATP