Grade 10 Bio Chapter 2

An organ

an organized group of tissues that performs a specific function.

the skin

The largest organ in your body. protects the inner cells from damage, acts as a defence against disease organisms, insulates, releases heat, and excretes bodily wastes. The skin is made up of two different layers of tissues: the epidermis and the dermis

Epidermis

the outer protective layer that is made up of epithelial tissue. The epidermis prevents bacteria and viruses from entering your body. The epidermis is also able to make vitamin D when the skin is exposed to ultraviolet radiation from the Sun.

Dermis

the inner layer of the skin and is made up of connective tissue, nervous tissue, and muscle tissue. Connective tissues provide structure and support. Blood and blood vessels are types of connective tissue. When you are hot, the blood vessels in your skin dilate, or become bigger, so that they can release excess heat. Pores in the skin secrete sweat produced in sweat glands to cool the body. Layers of fat, another type of connective tissue at the base of the dermis, provide insulation. The dermis contains nerves that sense pain, pressure, heat, and cold and send information to the brain.

The lungs

a pair of organs involved in respiration. Your lungs allow you to breathe in oxygen and breathe out carbon dioxide. The lung is made of connective and epithelial tissue. Humans have two lungs that sit in a cavity in the chest area. The lungs are coated with two sacs of connective tissue separated by a thin layer of fluid.

Respiratory System

When you breathe in air through your nose or mouth, the air passes through the pharynx into your trachea. The trachea is a flexible tube that is ringed with cartilage. Air moves down the trachea to the bronchus, into smaller bronchial tubes, and then into tiny air sacs, called alveoli, which are made of a thin layer of epithelial tissue. Alveoli are surrounded by thin-walled blood vessels called capillaries (Figure 2.5). Each lung contains about 150 million alveoli. Oxygen travels from the alveoli through the capillaries into the blood. Carbon dioxide travels from the bloodstream across the alveoli to the air in the alveoli.

The heart

a muscular pump that supplies blood to all parts of the body. The heart is divided into four chambers: the left and right atria, and the left and right ventricles. The heart serves as a pump to deliver blood to the lungs, to the heart itself, and to the rest of the body.

esophagus

the tube that food travels down once it enters your body. an organ of digestion. The food moves along the esophagus because of the rhythmic constriction and relaxation of the smooth muscles that line the esophagus. This movement is known as peristalsis. The esophagus is lined with a protective layer of epithelial tissue.

stomach

made of epithelial, connective, nervous, and muscle tissues. The stomach churns food and mixes it with digestive juices and enzymes.

intestines

two of them: small and large. areas of chemical digestion and removal of wastes.

organs of digestion (in order)

mouth, glands, tongue, esophagus, stomach, small intestine, large intestine, rectum, anus.

Plant organs

the roots, the leaves, the stem, and the flower or fruit

The Roots

• anchor the plant in the soil

• collect water from surrounding soil and transport it to the stem

• store food that is made in other parts of the plant

• the bottom of the root is covered with protective epidermal tissue known as the root cap

• just below is a layer of meristematic tissue, which allows the root to grow

• there are also layers of ground tissue and vascular tissue that make up the centre of the root

The Leaf

The tissues in a leaf work together to accomplish photosynthesis

• The vascular tissue carries water needed for photosynthesis from the root up the stem to the leaf.

• The sugar produced is carried by the vascular tissues to the rest of the plant.

• Carbon dioxide enters, and oxygen and excess water exit through openings in the leaf epidermal tissue called stomata.

• These openings are controlled by special cells known as guard cells.

Most of the leaf is made of a specialized ground tissue called mesophyll. Photosynthesis takes place in the mesophyll.

The Stem

The stem performs two major functions:

• transports water and nutrients throughout the plant

• supports the leaves and flowers

The tissues that make up the stem reflect these functions:

• Epidermal tissue provides a protective covering and allows for the exchange of gases and water vapour.

• In most plants, the epidermal tissue secretes a waxy substance known as the cuticle that forms a protective coating and reduces water loss.

• Ground tissue provides the stem with strength and support.

• Vascular tissue transports substances around the plant.

The Flower

the reproductive structure of the plant. produces seeds.

Organ systems

Organs that function together form.

integumentary system

skin, hair, nails, glands

• covers and protects body

• glands help control body temperature

skeletal system

bones, cartilage

• supports body

• allows movement

• protects the body

muscular system

skeletal muscle, smooth muscle, cardiac muscle, tendons, ligaments

• works with skeletal system to provide movement

• moves materials within body

digestive system

mouth, esophagus, stomach, pancreas, gall bladder, liver, intestines, rectum

• ingestion

• digestion

• absorption of nutrients

• elimination of solid wastes

respiratory system

nose, mouth, trachea, lungs, bronchi, bronchioles, alveoli, diaphragm

• exchange of gases

circulatory system

heart, blood vessels, blood

• transportation of materials (such as oxygen, nutrients, hormones, and wastes) within body

The heart acts as a pump to transport and regulate the flow of blood through a series of blood vessels: arteries, veins, and capillaries.

nervous system

brain, nerves, spinal cord

• controls body functions

• coordinates responses and activities

endocrine system

glands (pituitary, hypothalamus, thyroid, adrenals), pancreas, ovaries (in females), testes (in males)

• controls growth and development

• controls metabolism

excretory system

skin, kidney, bladder, ureter, urethra

• elimination of wastes

reproductive system

ovaries, fallopian tubes, vagina, uterus (in females); testes, epididymis, vas deferens, penis, urethra (in males)

• reproduction

lymphatic system

white blood cells, thymus, spleen, lymph nodes, lymph vessels

• protects body from disease

• circulates fluid called lymph

• absorbs and transports fats

Absorption

the process bywhich food that has already been broken down passes through the walls of the intestine into the bloodstream. Absorption takes place mainly in the small intestine.

Breathing

Your lungs are housed in your chest cavity, which is enclosed by the ribs, chest muscles, and the diaphragm.

• Inhale, your rib cage rises and your diaphragm contracts and moves downward - increases the size of your chest cavity.

• the internal air pressure of the cavity is less than the air pressure in the environment, so air rushes into your lungs to equalize the pressure.

• When you exhale, your rib cage lowers and your diaphragm relaxes and moves upward, decreasing the size of your chest cavity.

• The decrease in the volume of the cavity causes an increase in the internal air pressure in the cavity.

• Air moves out of your lungs.

arteries

thick-walled vessels that carry blood away from the heart to the tissues. The thickened muscular walls of the arteries allow them to withstand the force of the blood that is pumped from the heart.

Veins

carry blood back to the heart. The blood flowing through the veins is at a lower pressure than that in the arteries. Therefore, veins have thinner walls than arteries. Veins also contain valves so that the blood does not flow backward.

Capillaries

the smallest blood vessels in your body; they are about one cell thick. Oxygen (O2) and carbon dioxide (CO2) flow in and out of capillaries by the process of diffusion.

plant organ systems

a shoot system and a root system. The shoot system is everything that is above ground: the stem, leaves, buds, flowers, and fruits. The root system is everything underground, as well as aerial roots even though they are above ground.

homeostasis

“steady state” - there is an acceptable range of physical and chemical conditions in which body cells, tissues, and organs can operate efficiently. To keep the body within this acceptable range, different organ systems must work together to maintain homeostasis in the body.

interdependent

the action of one system contributes to the action of another system. organ systems are interdependent.