Animal and Plant OrgansSNC2D Biology

The Hierarchy of StructureLevel 5 Organism (many different organ systems working together

Level 4 System (one or more organs that work together to perform a body function)

Level 3 Organ (structure made of two or more types of tissue that work together to do a specific task)

Level 2 Tissue (group of similar cells that perform the same function)

Level 1 Cell (the most basic unit of living things)

OrgansSimilar to cells that work together to form tissues, a group of tissues that work together to perform a complex task are known as organs.

Organ

● Different tissues working together to perform a complex task

Animal OrgansThe Terminologia Anatomica (TA) states that there are over 7500 different named parts in the human body, many of which are organs.

Among them we have:

● Skin● Lungs● Heart● Stomach

Are you able to think of any others?

Animal Organs - The Skin● The skin is the largest organ in your body and is your first line of defense

from external factors

● It is made up of two different layers; the epidermis and the dermis

○ Epidermis: The outer protective layer of the skin. Made up of epithelial tissue.

○ Dermis: The inner layer of the skin. Made up of connective tissue, nerve tissue, and muscle tissue.

Animal Organs - The LungsThe lungs are a pair of organs that are involved in respiration. Your lungs allow you to breathe in oxygen and breathe out carbon dioxide. The lungs are made of connective tissue and epithelial tissue.

When you breathe, air passes through the pharynx, the trachea, the bronchus, and smaller bronchial tubes into tiny air sacs, called alveoli. These alveoli are surrounded by thin wall blood vessels called capillaries. Oxygen travels from the alveoli through the capillaries into the blood.

Animal Organs - The HeartThe heart is a muscular pump that supplies blood to all parts of the body.

● An adult human heart is weighs about 300g

● In an average lifetime, the heart beats about 3.5 billion times

The heart is divided into four chambers: the left and right atria, and the left and right ventricles.

Animal Organs - The StomachWhen you eat, various organs assist with the digestive process. One of these organs is the stomach.

● The stomach is made of epithelial, connective, nervous, and muscle tissues.

● An adult human stomach can hold around 1.5 liters (nearly half a gallon) of food/drink.

● Food doesn’t break down completely in the stomach. In fact, most of digestion happens in the small intestines.

Humans vs. Other AnimalsAll animals have organs to perform complex tasks. However, some animals have their organs arranged differently, lack certain organs, or have several of the same organ.

Plant OrgansA flowering plant is made of four kinds of tissues: epidermal, ground, vascular, and meristematic. These plant tissues group together to form organs that perform special functions for the plant.

A plant has four distinct organs:

● The roots● The stem● The leaf● The flower

Plant Organs - The RootsThe tissues in the roots work together to accomplish many different functions.

● They anchor the plant in the soil, which permits the plant to grow without toppling over

● The roots also collect water from the surrounding soil and transport it to the stem, and store food that is made in other parts of the plant

The roots are composed of meristematic,epidermal, vascular, and ground tissue.

Plant Organs - The StemThe stem performs two major functions:

● It transports water and nutrients throughout the plant

● It supports the leaves and flowers

The epidermal, vascular, and ground tissues that make up the stem reflectthese functions

Plant Organs - The LeafTypically, a plant leaf is very flat and thin in order to maximize the surface area directly exposed to sunlight and promote photosynthesis. The leaf is composed of epidermal, vascular, and ground tissues.

● Most of the leaf is made of a specialized ground tissue called mesophyll

● The mesophyll is where photosynthesis takes place

Plant Organs - The FlowerThe Flower is the reproductive structure of the plant. The flower contains male organs called stamens and female organs called the pistil.

● Each stamen consists of a filament with an anther at the tip. The anther produces pollen, which are the male sex cells.

● A pistil consists of the ovary, style, and stigma. Female sex cells called eggs are located in the ovary.

When pollen and egg unite, the fertilized cell becomesan egg.

Recap● Similar to cells that work together to form tissues, a group of tissues that

work together to perform a complex task are known as organs.

● Animal organs include the skin, stomach, lungs, and heart among many others.

● All animals have organs to perform complex tasks. However, some animals have their organs arranged differently, lack certain organs, or have several of the same organ.

● Plant organs include the roots, stem, leaf, and flower.