Organismic Biology

Lecture 4 NatSci IIJosephine B. Guerrero, MDAsst. Professor, Department of Biology

Levels of Organization Cells Tissues Organs Organ Systems Organism

TISSUES

Plant Tissues:1. Meristematic – immature, undifferentiated,

rapidly dividing; apical meristem and lateral meristem

2. Fundamental Parenchyma – thin-walled; cortex and pith Collenchyma – irregularly thickened; periphery of

stems and leaves Sclerenchyma – thick walls; fibers, sclereids (seeds

and seed coats)3. Vascular- responsible for the movement of

materials inside the plant; xylem vs. phloem

Parenchyma Collenchyma Sclerenchyma

Animal Tissues:1. Epithelial – covers external and internal

surfaces; attached to a basement membrane2. Connective – “connects” or supports other

structures , “fills” body layers or spaces3. Muscle – capable of contraction for movement4. Nervous – for propagation of electrical impulses5. Reproductive – gametes for reproduction

Epithelial Tissues According to Shape of Cells

Squamous – flat, polygonal Cuboidal – equal height, width, thickness Columnar – greater height than width and

thickness Transitional – varies in shape from cuboidal

to squamous depending on the degree of distention of the organ where it is found

Epithelial Tissues According to Number of Layer of Cells

Simple – only one layer of cells directly attached to basement membrane

Stratified – more than one layer; the innermost layer is attached to the basement membrane

Pseudostratified – appears to have several layers; in reality, only one layer

Simple Squamous

Simple Cuboidal

Simple Columnar

Stratified Squamous

Pseudostratified ciliated columnar

Transitional

Components of Connective Tissue1. Matrix – mucopolysaccharides, ground

substance or “background” where other components are embedded

2. Fibers Collagen – most resilient Elastic – has the ability to be stretched and

return to its original configuration Reticular – fine, branched fibers; most

delicate

Components of Connective Tissue3. Cells

Fibroblast – produces fibers and matrix Osteoblast, osteocyte, osteoclast –in bone Chondroblast, chondrocyte – in cartilage Adipocyte – in adipose tissue Macrophage – phagocytic cell Mast cell – produces chemical mediators as

histamine for inflammation

Connective TissueGeneralized Connective Tissue

Specialized Connective Tissue

Loose or Areolar CT

Dense CTDense Collagenous RegularDense Collagenous Irregular

Dense Elastic RegularDense Elastic Irregular

Adipose

Cartilage Hyaline Elastic Fibrocartilage

Bone

Blood

Loose or Areolar Tissue

Dense Connective Tissue

Adipose

Hyaline Cartilage

Elastic Cartilage

Fibrocartilage

Bone

Blood

Skeletal Muscle – striated, voluntary; multinucleated; peripheral nuclei; cylindrical cells

Cardiac Muscle – striated, involuntary; uninucleated; central nuclei; cylindrical branched cells

Smooth Muscle – nonstriated, involuntary; uninucleated; central nuclei; fusiform or spindle-shaped cells

Nervous Tissue

Reproductive Tissue

Male Gamete = sperm

Female Gamete = ovum

ORGAN SYSTEMS

Organ Systems in Plants:Root System (usually underground)Shoot System (usually above ground)

Integumentary System: Functions mainly for protection Other functions include thermoregulation,

secretion, absorption, excretion Derived structures from integument

include scales, feathers, horns, claws, nails and hair

Types of Integument Amoeba – cell membrane Paramecium – pellicle Soft-bodied aquatic invertebrates or those which

thrive in most environments – single-layer epidermis

Worms, arthropods – cuticle; cuticle of arthropods have chitin

In snails and other animals, the epidermis secretes an exoskeleton.

Section of Human Skin

Skeletal SystemTypes:1. Hydroskeleton2. Exoskeleton3. Endoskeleton

Function:1. Support2. Form3. Attachment of

muscles4. Protection

EXOSKELETON

Human Skeletal System

Movement in Organisms Amoeboid movement- Amoeba; exhibited

by some cells in complex organisms Contractile fibrils in cilia and flagella –

ciliates and flagellates Smooth and striated muscles (in layers or

separate muscles) – cnidarians, arthropods, worms, molluscs, vertebrates

Organization of Muscle in Vertebrates

Human Muscular System

Modes of Digestion1. Single cell prokayotes/eukaryote –

intracellular, by enzymatic action2. Fungi (molds & mushrooms) – absorptive3. Plants – rare via external acid4. Animals – internal; complex combination

of mechanical and chemical processes

Human Digestive System

Chemical DigestionNeeded to convert macromolecules to simplest forms

that can be absorbed CHO to monosaccharides CHON to amino acids Fats to glycerol and fatty acids Carried out by:

1. Salivary glands – amylase2. Stomach – pepsin3. Small intestine – pancreatic amylase, trypsin,

chemotrypsin, carboxypeptidase, pancreatic lipase, dissacharidases, dipeptidases,

Modes of Circulation:1. Plants – xylem (transpiration cohesion)

phloem (active transport osmosis)

2. Lower animal forms (open type) – blood or circulatory fluid directly bathes cells

3. Higher animal forms (closed type) – blood or circulating fluid stays inside blood vessels (arteries, veins, capillaries)

Requires a pumping organ, circulating fluid and the channels for the fluid

Human circulatory system

Pathway of blood thru the heart

Formed Elements in the Blood

Lymphatic System

Immunity Non-specific Immune Mechanisms or

Innate Immunity Intact skin and mucous membranes as

protective barrier Chemical mediators: lysozymes, histamine,

interferons Phagocytic cells Inflammation

Immunity Specific or Adaptive Immunity – exhibits

specificity and memory Cell-mediated Immunity or Cytotoxic

Immunity – T cells/T lymphocytes (Killer T cells) Antibody-mediated or Humoral Immunity –

B cells/B lymphocytes produce antibodies (Immuneglobulins)

How do we acquire adaptive immunity? Natural vs. Artificial Means Active vs. Passive Means

Active – give the antigen and stimulate body to produce its own defenses; more permanent

Passive – give the pre-formed immuneglobulins or antibodies; faster but short-lasting

Natural Active – when an individual gets exposed to the pathogen or antigen; may or may not become sick

Natural Passive – From mother to infant through breastfeeding and through placental circulation

Artificial Active – Vaccinations Artificial Passive – Immuneglobulin

therapy

Modes of Respiration1. Single cell animals and some lower forms -

diffusion2. Plants – cellular3. Aquatic animals – gills4. Terrestrial animals – lungs or similar forms

Human Respiratory System

Forms of Respiration

External Respiration or Mechanical Ventilation – involves exchange of air/gases between the body and the environment Inspiration or

Inhalation Expiration or

Exhalation

Forms of Respiration Internal Respiration -

involves exchange of gases at the level of the tissues Exchange of oxygen

and carbon dioxide in pulmonary capillaries and in systemic capillaries

Forms of Respiration Cellular Respiration

involves utilization of oxygen in cells for production of ATP