3º ESOThe organization of the

human body

Organisation of living matter

Organisation of living matter

Human beings are living things:

• Composed of biomolecules (proteins, lipids and carbohydrates)

• Made of cells (60 trillions cell). So they are multicellular organisms• Eukaryote cells: these have organelles and DNA enveloped

by a cover

• They perform the three vital functions:• Nutrition: they feed on other living things (heterotrophic)• Interaction• Reproduction

Levels of organisation of the human being

especializadas

de varios tipos

Mismo tipo de tejido Distinto tipo de tejido

Cell Types• Prokaryotic

• Eukaryotic

Characteristics of All Cells• A surrounding membrane• Cytoplasm– cell contents in thick fluid• Control center with DNA (Nucleus)

Representative Animal Cell

Cytoplasm• Viscous fluid containing organelles• components of cytoplasm

– Interconnected filaments & fibers – Fluid = cytosol– Organelles (not nucleus)– storage substances

Nucleus • Control center of cell

• Double membrane

• Contains – Chromosomes– Nucleolus

Nuclear Envelope• Separates nucleus from rest of cell

• Double membrane

• Has pores

Nucleolus• Most cells have 2 or more• Directs synthesis of RNA• Forms ribosomes

Rough Endoplasmic Reticulum• Ribosomes attached to surface

– Manufacture protiens– Not all ribosomes attached to rough ER

• May modify proteins from ribosomes

Smooth Endoplasmic Reticulum

• No attached ribosomes• Has enzymes that help build molecules

– Carbohydrates– Lipids

Golgi Apparatus• Packaging & shipping station of cell

Lysosomes• Contain digestive enzymes• Functions

– Aid in cell renewal– Break down old cell parts – Digests invaders

Vacuoles• Membrane bound storage sacs• More common in plants than animals• Contents

– Water– Food– wastes

Mitochondria• Break down fuel molecules (cellular respiration)

– Glucose– Fatty acids

• Release energy– ATP

Cytoskeleton• Made of proteins• Supports cell shape and function• Keep organelles organized

Centrosome• Near the nucleus.• Formed by two tubular structures: centrioles

(made of proteins)• Coordinate cytoesqueleton movement and

cell division

Exchange with the environment• Cells have to exchange substances to live through its

semipermeable membrane:– Diffusion: movement of small molecules from greater

to lower concentration.

– Osmosis: passage of water from the more diluted to the more concentrated medium

– Active transport: movement of substances from lower to greater concentration

– Endocytosis: cell sometimes incorporates large particles by membrane collapsing . The opposite process is called exocytosis.

Cellular differentiation• After fertilization , egg cell begin to divide on identical cells (stem cells) till

gastrulation stage on 3rd week

Specialised cells (muscle ones for instance):• Makes a particular job. Muscle cells contract and relax to produce movement• Develop a characteristic shape. Muscle cells are usually very long .• There are changes in their cytoplasm .In muscle cells are abundant

mitocondria for energy-producing and cytoskeletal filaments .

Those 60 trillion cells in a human body have the same nucleus DNA

Types of tissuesEpithelial tissues: cells arranged very closely together• Epithelium tissue Lining the surface of the body (skin and hollow cavities inside

the body)

• Glandular epitheliumreleases substances with different functions (pancreas and liver). Sometimes form structures called glands (saliva glands)

Type of cells

Intercellular substance among them

Types of tissues

Connective tissues: supports and/or connects other tissues. Produce a lot of extracellular substances.• Connective tissue Located in the deepest layer of our skin (dermis) and “stuffing”

between organs

• Adipose tissueenergetic reserve. Thermal insulating.

• Bloodtransports nutrients and oxygen

• Bone tissuerigid tissue because of mineral salts it contains in its matrix

• Cartilaginous tissue protects joints from the bones, and strengthens some structures.

Types of tissuesMuscle tissue• Composed of elongated cells called muscle fibres

• These muscle cells contract and relax causing the body to move

• Three different muscle tissues:

• Striated muscle tissue: contract voluntary (locomotor system)

• Smooth muscle tissue: contract involuntary (stomach or intestine)

• Cardiac muscle tissue: striated but contract involuntary

Types of tissuesNervous tissue

• Composed of cells called neurons.

• Coordinates the functioning of the organism.

Organ

SystemsNutrition• Digestive systemPrepares food to be used by cells

• Respiratory systemSupplies O2 to the blood and takes away CO2

• Circulatory systemBlood distribute nutrients and oxygen. Picks up waste products

• Excretory systemPicks up waste products from blood and discharges them from the body. Regulates wáter content.

SystemsReproduction• Reproductive system Ensures our survival over time. Involves both,

male and female reproductive organs

SystemsInteraction (to internal and external enviroment)

• The sensory organs Pick up information and enable the body to adapt and survive

• The nervous systemReceives information from outside and inside the body. Coordinates all the body functions

• The endocrine systemMade up of glands, special organs that release substances (hormones) to the blood. Different effects on the body.

• The skeletal and muscular systems (locomotor system) Formed by bones and muscles respectively. Responsible for a person’s movement.

SystemsNotice that:• The nervous and endocrine systems coordinate all the systems in the

body

• Sense organs perceive internal and external stimuli

• The nervous system sends orders to the organs in order to respond to those stimuli

• The endocrine system controls many of the reactions that take place inside cells