exam 1 human biology

The characteristics of life

have a different molecular composition than nonliving things

require energy and raw materials

are composed of cells

maintain homeostasis

respond to their external environment

grow and reproduce

populations of living things evolve

Living things are grouped according to characteristics

Three domains

domain bacteria

domain archaea

domain eukarya

Domain eukarya has four kingdoms

kingdom protista

kingdom animalia

kingdom fungi

kingdom plantae

Fundamental Criteria used for classification

Presence or absence of a nucleus

• domain bacteria and domain archaea lack a membrane-bound nucleus

• domain eukarya has a membrane-bound nucleus

Number of cells

• unicellular

• multicellular

types of metabolism

Domain Eukarya includes four kingdoms

protista: unicellular and simple multicellular, eukaryotic (protozoa, algae, slime molds)

plantae: multicellular, eukaryotic, photosynthetic

animalia: multicelluar, eukaryotic, heterotrophic

fungi: eukaryotic, decomposers (molds, mushrooms)

Classification of humans (homo sapiens)

classification of humans

domain - eukarya

kingdom - animalia

phylum - chordata

class - mammalia

order - primates

family - hominidae

genus - homo

species - sapiens

Living things are grouped according to characteristics

• Smallest units of classification system is species 

  • One or more populations of organisms 

    • Similar physical and functional characteristics 

    • Can interbreed and produce fertile offspring 

• Second smallest unit is genus 

• All living human beings belong to the same genus and species 

  • Homo sapiens

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Human biology can be studied on any level of biological organization

• Atom and molecule 

• Cell

• Tissue

• Organ

• Organ System 

• Organism 

• Population

• Community 

• Ecosystem 

• Biosphere

Science is Both a Body of Knowledge and a Process

• Science is the study of the natural world 

• Science is two things 

  • Knowledge about the natural world 

  • The process used to acquire knowledge 

    • Called the scientific method 

The Scientific Method is a Process for Testing Ideas 

• Steps in the scientific method

  • Observe and generalize 

  • Formulate a hypothesis

  • Make a testable prediction 

Experiment or observe
Modify the hypothesis as necessary and repeat

The Scientific Method is a Process for Testing Ideas

• Observe and Generalize 

  • Inductive reasoning: Make generalizations based on observations about the world 

  • Example: 

    • Observation: Every winter in the past was colder than the preceding summer. 

    • Generalization: Winter will always be colder than summer 

• Formulate a hypothesis 

  • A hypothesis is a tentative statement about the natural world 

• Make a testable prediction 

  • Hypotheses should be tested under many different conditions

  • Testable predictions 

    • Should be based on the hypothesis 

    • Should employ deductive reasoning 

    • Are often in the form of if or then statements 

    • Should be specific in order to be testable 

• Experiment and observe 

  • Truth or falsehood of prediction is tested by observation and experimentation 

  • Experiment: a carefully planned and executed manipulation of the natural world 

    • In controlled experiments, all but one variable are accounted for 

• Modify the hypothesis as necessary and repeat steps three and four 

  • If the prediction is false, the hypothesis must be modified 

  • If the prediction is true, only one small part of the hypothesis has been tested. Further testing required 

  • Hypotheses cannot be proven true, only supported or disproved

Making Findings Known 

• Findings can be disseminated in peer-reviewed journals 

  • Experts must approve articles before publication

  • Results are assumed to be valid only for conditions under which experiment was done

  • Usually the most accurate scientific information is contained 

A well-tested hypothesis becomes a theory

• For a hypothesis to become a theory it must 

  • Be broad 

  • Be extensively tested

  • Be supported over time

  • Explain a broad range of facts

  • Have a high degree of reliability 

• Theories may be refuted in the future. 

Sources of Scientific information vary in style and quality 

• Peer-reviewed journals 

• Science magazines and nonfiction books 

• General interest new magazines, daily newspapers 

• Internet

Learning to be a critical thinker

• Become a skeptic

• Learn how to read graphs 

• Appreciate the value of statistics 

• Distinguish anecdotes from scientific evidence 

• Separate facts from conclusions 

• Understand the differences between correlation and causation 

The role of science in society 

• Science improves technology and the human condition

• Science has limits

• Science helps us to make informed choices

Tissues: Groups of Cells with a Common Function

• Four primary tissues 

  • Epithelial tissues 

  • Connective tissues 

  • Muscle tissues 

  • Nervous tissue

Epithelial Tissues

• Two basic purposes 

  • Line body cavities and cover surfaces 

  • Glandular epithelia 

    • Epithelial cells adapted to form glands 

      • Exocrine glands

        • Secrete products into hollow organs or ducts 

      • Endocrine glands 

        • Secrete products (hormones) into the blood for distribution throughout the body 

Epithelial Tissues: Classification According to Shape

• Three types, based on shape 

  • Squamous 

    • Flattened cells 

    • Line vessels, part of lungs, body surface 

  • Cuboidal 

    • Cube shaped 

    • Form lining of tubules, glandular tissue 

  • Columnar 

    • Column shaped 

    • Line respiratory, digestive, reproductive tracts

Epithelial Tissues: Further Classification Based on Number of Layers 

• Number of layers 

  • Simple/single-layered 

    • Adapted for diffusion across cell barriers 

    • Line glands, and respiratory, digestive, reproductive systems 

  • Stratified/multiple-layered 

    • Provide protection, as in the skin surface

The Basement Membrane Provides Structural Support

• Basement Membrane 

  • Noncellular layer directly beneath epithelial tissue 

  • Composed of proteins secreted by epithelial cells and connective tissue 

  • Provides structural support to overlying cells 

  • Attaches epithelial layer to underlying tissues

Cell Junctions - Hold Adjacent Cells Together 

• Tight junctions 

  • Seal plasma membranes tightly together 

  • Digestive tract lining, bladder lining 

• Adhesion junctions/spot desmosomes 

  • Permit some movement between cells 

  • Allow tissues to stretch and bend 

  • Skin 

• Gap junctions 

  • Protein channels enable movement of materials between cells 

  • liver, heart

Connective Tissues 

• General functions 

  • Support softer organs of body 

  • Connect parts of body 

  • Store fat 

  • Produce blood cells 

• Contain cells embedded in nonliving extracellular matrix 

• Matrix provides the strength

• Two general types

  • Fibrous and specialized

Fibrous Connective Tissue 

• Function: provides strength and elasticity 

• Contains fibers and cells embedded in gel-like ground substance (matrix) 

• Matrix: intercellular material giving the connective tissue its characteristics 

• Cells: fibroblasts, macrophages, lymphocytes, and neutrophils

• Fibers: collagen, elastic, and reticular 

• Four general types 

  • Loose: surrounds internal organs, muscles, and blood vessels

  • Dense: forms tendons, ligaments, deeper layers of skin

  • Elastic: surrounds hollow organs (stomach and bladder) that change shape or size regularly 

  • Reticular: makes up internal framework of soft organs (liver) and the lymphatic system

Specialized Connective Tissues Serve Special Functions

• Cartilage: transitional tissue from which bone develops; maintains shape of certain body parts (nose, ears), cushions vertebrae (vertebral disks), lines joint cavities. 

• Bone: forms the skeleton 

• Blood: fluid matrix of plasma, red blood cells, white blood cells, and platelets; transports materials.

• Adipose tissue: fat cells; functions in insulation, protection, and energy storage

Muscle Tissue Contracts to Produce Movement 

• Skeletal muscle 

  • Moves body parts 

  • Voluntary, multinucleated 

• Cardiac muscle 

  • Functions in the heart 

  • Involuntary, single nucleus 

• Smooth muscle 

  • Surrounds hollow structures 

  • Involuntary, single nucleus

Nervous Tissues Transmit Impulses 

• Neuron: specialized nervous system cell 

  • Function: generate and transmit electrical impulses 

  • Structural components: cell body, dendrites, axon 

• Glial cells 

  • Function 

    • Surround and protect neurons 

    • Provide nutrients to neurons

Organs and Organ Systems Perform Complex

• Organs 

  • Contain two or more tissue types joined together; perform specific functions 

• Organ systems 

  • Groups of organs that perform a common function 

  • 11 organ systems make up the human body

  • Examples 

    • Digestive system: mouth, throat, stomach, intestines, and liver 

    • Lymphatic system: lymph nodes, tonsils, and spleen

Body Cavities

• Anterior cavity 

  • Thoracic cavity 

    • Two pleural cavities 

    • Pericardial cavity

  • Abdominal cavity 

• Posterior cavity 

  • Cranial cavity

  • Spinal cavity 

• Tissue membranes (serous membranes) line body cavities

Tissue Membranes Line Body Cavities

• Serous membranes 

  • Line and lubricate internal body cavities 

  • Reduce friction between organs 

• Mucous membranes 

  • Line airways, digestive tract, reproductive tract 

  • Lubricate surface, capture debris 

• Synovial membranes 

  • Line spaces in moveable joints 

• Cutaneous membranes 

  • Form outer covering (skin)

Describing Body Position or Direction

• Three body planes 

  • Midsagittal 

    • Divides body into left and right sides 

  • Frontal 

    • Divides body into front and back 

  • Transverse 

    • Divides body into top and bottom 

• Terms to describe relative position

  • Anterior: at or near the front

  • Posterior: at or near the back 

  • Proximal: nearer to the body trunk 

  • Distal: farther away from the body trunk 

  • Superior: situated above or directed upward 

  • Inferior: situated below or directed downward

The Skin as an organ system 

• The proper name is integumentary system 

• Includes skin, hair, nails, glands 

• Functions 

  • Protects from dehydration

  • Protects from injury 

  • Serves as defense against microorganisms 

  • Regulates body temperature 

  • Makes vitamin D 

  • Provides sensation

Skin consists of epidermis and dermis

• Epidermis 

  • Outer layer 

  • Stratified squamous epithelial cells 

  • No blood vessels 

  • Two major cell types 

    • Kerattinocytes: provides a tough waterproof protein (keratin)

    • Melanocytes: provide dark pigment (melanin)

• Dermis 

  • Primarily dense connective tissue 

  • Lies underneath the epidermis 

  • Supports tissues 

  • Fibers: provide strength and elasticity 

    • Collagen 

    • Elastic 

  • Cells 

    • Fibroblasts (most abundant) 

    • Mast cells 

    • White blood cells 

    • Fat cells

Accessory Structures of Dermis 

• Hair 

  • Shaft above the skin surface 

  • Follicle 

• Smooth muscle 

  • Attached to hair follicle, raises hair to upright position 

• Sebaceous (oil) glands 

  • Secrete sebum, which moistens and softens skin

• Sweat glands 

  • Secrete sweat to help in temperature regulation

• Blood vessels 

  • Supply nutrients, remove waste, assist in temperature regulation

• Sensory nerve endings 

  • Detect heat, cold, touch, deep pressure, vibration

Multicellular Organisms must maintain homeostasis

• Maintenance of relative constancy of the conditions of the internal environment

• Negative feedback control system: deviations from normal are detected and counteracted 

• Components of a negative feedback control system

  • Controlled variable 

  • Sensor 

  • Control center 

  • Effector

Components of a negative feedback control system

• Controlled variable: any physical or chemical property that might vary and must be controlled to maintain homeostasis 

• Sensor (receptor): monitors current value for controlled variable and sends information to control center 

• Control center: receives input from sensor, compares value to set point, signals the effector if necessary 

• Effector: takes action to correct the imbalance, based on information from the control center

Negative Feedback Helps maintain core body temperature

• Controlled variable: body temperature 

• Sensors: temperature sensors in skin and internal organs 

• Control center: hypothalamus 

• Effector: 

  • Blood vessels 

  • Sweat glands 

  • Skeletal muscles

Positive Feedback Amplifies Events

• A change in a controlled variable causes a series of events that amplifies the original change 

• Example: process of childbirth 

• Positive feedback is not a mechanism for maintaining homeostasis

Skeletal System Consists of Connective Tissue

• Three types of connective tissue 

  • Bone 

    • Hard elements of the skeleton

  • Ligaments

    • Dense fibrous connective tissue 

    • Attach bones to other bones

  • Cartilage 

    • Specialized connective tissue, fibers of collagen and elastic in a gel-like ground substance 

    • Cushions vertebrae 

    • Reduces friction in joints

Bones are the hard elements of the skeleton

• Hard, rigid appearance due to nonliving extracellular crystals of calcium minerals 

• Living tissue containing several types of cells involved in bone formation and remodeling 

• Five important functions of bone 

  • Support 

  • Protection 

  • Movement 

  • Blood cell formation 

  • Mineral storage 

    • Calcium 

    • Phosphate

Bone Contains Living Cells

• Bone: hard inorganic matrix of calcium salts 

  • Compact bone: forms shaft and ends, contains marrow space 

    • Yellow bone marrow (mostly fat) in marrow space 

  • Spongy bone: trabeculae form lattice-like support

    • Spaces may contain red bone marrow

  • Cells: osteoblasts, osteocytes, osteoclasts

  • Types: long, flat, irregular 

• Osteons/haversian system: cellular arrangement 

• Periosteum: connective tissue covering

Ligaments Hold Bones Together

• Function: attach bone to bone 

• Made of dense fibrous connective tissue 

• Provide strength in joints yet enable movement

Cartilage Lends Support

• Function: provides support under pressure 

• Types 

  • Fibrocartilage 

    • Intervertebral disks between vertebrae 

    • Menisci in knee joints 

  • Hyaline 

    • Forms embryonic structure, which later forms bone

    • Covers and protects ends on long bones in joints, providing protection, reducing friction 

  • Elastic cartilage 

    • Flexible, outer ear, epiglottis

Bone Development Begins in the Embryo

• Early fetal development: cartilage model forms 

  • Formed by chondroblasts (cartilage-forming cells)

• Later fetal development: osteoblasts replace cartilage with bone

• Childhood: primary and secondary ossification sites formed 

• Adolescence: elongation at growth plates

Bone Development is regulated by hormones

• Preadolescence 

  • Growth hormone stimulates bone lengthening 

• Early adolescence 

  • Estrogen and testosterone stimulate bone lengthening 

• Late adolescence 

  • Estrogen and testosterone cause replacement of cartilage growth plates with bone

Mature Bone Undergoes Remodeling and Repair

• Remodeling: changes in shape, size, strength 

  • Dependent on diet, exercise, age 

  • Weight-bearing exercise increases overall bone mass and strength 

• Bone homeostasis depends on balance of osteoblast and osteoclast activity 

• Osteoporosis: loss of bone mass due to prolonged imbalance of osteoblast and osteoclast activity

Bones can change in shape, size, and strength

• Constant remodeling can change bone shape 

• Compressive stress causes electrical currents in bone 

• Electrical currents stimulate osteoblasts 

• New bone is deposited in areas of high compressive stress

• Bone is resorbed in areas of low compressive stress

• Weight-bearing exercise increases overall bone mass and strength

Cells involved in the development and maintenance of bone

• Chondroblasts: cartilage-forming cells 

• Osteoblasts: young bone-forming cells 

• Osteocytes: mature bone cells 

• Osteoclasts: bone-dissolving cells

Bone Cells are regulated by hormones

• Parathyroid hormone (PTH) 

  • PTH secretion increases when blood levels of Ca++ fall 

  • Stimulates osteoclasts to secrete more bone-dissolving enzymes 

• Calcitonin 

  • Calcitonin secretion increases when blood levels of Ca++ are high

  • Stimulates osteoblasts to add calcium and phosphate to bone

Bone Undergo Repair

1. Bone fracture

2. Hematoma forms at site of fracture 

3. Fibroblasts migrate to area to begin repair process

4. Tough fibrocartilage callus is formed at site of fracture by chondroblasts 

5. Osteoclasts remove dead damaged bone and remnants of hematoma 

6. Osteoblasts deposit new bone in area of fracture 

7. Repair process takes from weeks to months

Bones Fit together to form the skeleton

• 206 bones

• Four types of bones

  • Long (bones of limbs and fingers) 

  • Short (wrist bones)

  • Flat (cranial bones, sternum, ribs) 

  • Irregular (coxal bone, vertebrae)

The Skeleton Protects, Supports, and Permits Movement

• Provides support for soft organs 

• Protects many organs 

• Joints provide flexible movement of many parts of the body 

• Mineral (calcium, phosphorus) storage 

• Bone marrow: formation of blood cells

Skeleton organized into two groupings

• Axial skeleton - midline of body 

  • Skull, sternum, ribs, vertebral column, sternum 

• Appendicular skeleton - bones of the appendages and their attachment structures 

  • Pectoral girdle, arms, pelvic girdle, legs

Axial skeleton forms midline of the body

• Skull 

  • Cranial bones 

  • Facial bones

• Hyoid bone 

  • Does not articulate with any other bone 

  • Attachment for muscles of tongue, larynx, pharynx 

• Vertebral column 

• Ribs and sternum

The Skull: Cranial Bones

• Function: protect the brain 

• Cranial bones 

  • Frontal bone 

  • Parietal bones

  • Temporal bones

  • Sphenoid bone 

  • Ethmoid bone

  • Nasal bone

  • Lacrimal bones

  • Occipital bone

The Skull: Facial bones

• Maxilla 

• Palatine bones 

• Vomer bone

• Zygomatic bones 

• Sinuses - air spaces within several cranial and facial bones

Axial Skeleton: Vertebral Column

• Vertebral column

  • protects spinal cord

  • regions

    • cervical (neck): 7 vertebrae

    • Thoracic (chest): 12 vertebrae

    • Lumbar (small of the back): 5 vertebrae

    • Sacral (sacrum): 5 fused vertebrae

    • Coccygeal (coccyx): 4 fused vertebrae

  • intervertebral disks: cushion vertebrae; assist in movement and flexibility

Ribs and Sternum: Protecting the Chest Cavity

• Ribs 

  • Protect lungs, heart

  • 12 pair 

    • 10 pairs are attached to vertebrae in back, sternum in front 

    • Lowest two pair are “floating,” attached to vertebrae but NOT attached to sternum 

• Sternum 

  • Protects heart 

  • BreastboneRibs 

    • Protect lungs, heart

    • 12 pair 

      • 10 pairs are attached to vertebrae in back, sternum in front 

      • Lowest two pair are “floating,” attached to vertebrae but NOT attached to sternum 

  • Sternum 

    • Protects heart 

    • Breastbone

Appendicular Skeleton: Pectoral Girdle and Upper limbs

• Pectoral girdle: shoulder

  • Clavicles (collarbones)

  • Scapulas (shoulder blades) 

• Arms 

  • Upper arm: humerus 

  • Forearm: radius, ulna

  • Wrist: carpal bones (8) 

  • Hand (palm): metacarpal bones (5)

  • Fingers and thumb: phalanges (14)

Appendicular Skeleton: Pelvic Girdle and Lower Limbs

• Pelvic girdle (hip) 

  • Coxal bones (2), sacrum, pubic symphysis 

• Legs 

  • Upper leg (thigh): femur 

  • Knee cap: patella

  • Lower leg (calf): tibia, fibula

  • Ankle: tarsal bones (7) 

  • Foot: metatarsals (5) 

  • Toes: phalanges (14)

Comparison of Male and Female Pelvic Girdle

• Pelvic girdle in women 

  • Broader

  • Shallower

  • Wider opening

Joints (Articulations) form connections between bones

• Classified by degree of movement 

  • Fibrous joint 

    • Immovable 

    • Example: joints between flat bones of skull 

  • Cartilaginous joint 

    • Slightly movable, cartilage connection

    • Example: joints between adjacent vertebrae

  • Synovial joint 

    • Freely movable 

    • Bones separated by fluid-filled cavity

Synovial joints

• Joint capsule: synovial membrane + hyaline cartilage 

• Synovial membrane secretes synovial fluid as a lubricant 

• Hyaline cartilage acts as a cushion

• Types of synovial joints

  • Hinge joint

  • Ball and socket joint

• Tendons - join bone to muscle

Ligaments, Tendons, and Muscles strengthen and stabilize joints

• Ligaments: attach bone to bone in a synovial joint 

  • Example: ACL 

• Tendons: attach muscle to bone

  • Example: achilles tendon

• Both tendons and ligaments are composed to tough connective tissue containing collagen (strong, flexible) 

• Muscles further stabilize joints

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Diseases and Disorders of the Skeletal system

• Sprains 

  • Stretched or torn ligaments

  • Heal slowly (few cells and poor blood supply) 

• Bursitis and tendinitis 

  • Inflammation of bursae or tendons

• Arthritis: inflammation of joints

  • Osteoarthritis 

  • Rheumatoid arthritis 

• Oseoporosis: excessive bone loss