Chapter 6 Nelson Science Grade 8

Organisms

living systems with parts that work together to carry out the processes of life.

Bolus

The scientific name for swallowed food that enters your digestive system.

Chyme

When food leaves your stomach it is referred to as?

How long food can spend in your digestive tract

3 days.

Unicellular Organism

An organism made up of one cell. Perform some of the same life processes as multicellular organisms. Sense their surroundings via sensors.

Multicellular Organism

Organism made up of one or more cells. They all begin as a single-cell. As the number of cells increases, each cell becomes able to perform specific functions.

Plants, animals, fungi, protists, and bacteria

classification of living things

Plants

Multicellular organisms which make their food using photosynthesis. Can live on water or land.

Animals

Vertebrates are animals with a backbone, invertebrates are animals without a backbone. There are generally more invertebrates than vertebrates.

Fungi

An organism that absorbs nutrients from the environment. Most are multicellular, however some are unicellular.

Protists

Diverse group of organisms that are commonly found in wet or moist environments such as ponds, rivers, and mud. Can be unicellular or multicellular and have the organelles of a typical animal cell. Some protists are plant-like organisms that have chloroplasts and can perform photosynthesis. They must obtain food from their environment.

Bacteria

Simplest and most abundant unicellular organisms on Earth. They do not have a nucleus. Some types gather into groups called bacterial colonies.

Most microorganisms live in?

Most microorganisms live in water, so they rely on cilia, flagella, and pseudopods for survival.

What are the 4 kinds of differentiated cells?

muscle, fat, nerve, epithelial. These differentiated cells are then organized according to the function they perform - tissues, organs, organ systems.

Tissues

Perform a specific function and in certain cases protect internal and external surfaces.

What are the 4 kinds of tissues?

Epithelial, nervous, connective, muscle.

Organs

Different tissues assembled to form larger structures, such as skin, stomach, and the heart. They are made up of different types of tissues that work together to achieve one or more functions.

Organ systems

Never work alone, two or more organisms work together to perform a related function. Examples are the digestive system, and the circulatory system.

5 organ systems

Circulatory system, respiratory system, digestive system, musculoskeletal system, nervous system.

The heart

It powers the entire circulatory system and transports nutrients, oxygen, waste, heat, hormones, and immune cells throughout the body. It is a big, wet, muscly brute of a pump. It's one job is to maintain pressure.

Blood pressure

A measure of the amount of strain your arteries feel as your heart moves your blood around.

Approximately how many heartbeats in a lifetime?

2-3 billion

How much does the heart weigh?

250-350 grams

Where is the heart located?

mediastinum area, between lungs

The heart is a general system of?

Chambers, valves, veins, and arteries that all work together to circulate blood around your body.

Septum

Divides the heart.

Arteries

carry blood away from the heart.

Veins

carry blood back to the heart.

Pulminory Circulation Loop

Gets rid of carbon dioxide and brings in fresh oxygen from the lungs. Oxygenated blood goes to all other cells or organs.

Aorta

Largest artery in the body.

Systemic loop goes from _____ to ____, _____ to _____, and back to _____

Systemic loop goes from heart to lung, heart to body, and back to heart.

Ideal blood pressure?

120/80. 120 is the systolic blood pressure (when your heart is at work) and 80 is diastolic blood pressure (when your heart is at rest)

What is the first organ system to form?

Digestive system

What is other organ system is the digestive system run by?

Nervous system

Dogs have a _____ digestive period.

Short.

Cows have a ____ digestive period.

Long.

Humans have several _____ and _______ which aid in the digestive process.

Humans have several acids and enzymes which aid in the digestive process.

Secret to digestion?

Maximizing surface area.

Digestion begins where?

The mouth.

Chewing your food to break it down into smaller pieces allows what to further break down the food?

Acids and enzymes.

Average length of the small intestine?

7 metres.

Average length of the large intestine?

1.5 metres.

Inside the mouth, there is an enzyme that breaks down glucose called?

Salivary amylase.

In the stomach is gastric juice which is made up of what?

Pepsin, hydrochloric acid, mucus and water.

The large intestine is _____ than the small intestine.

The large intestine is wider than the small intestine.

The respiratory system is set up to take full advantage of what?

Bulk flow (breathing in many oxygen molecules) and simple diffusion (travelling across cell membrane).

Lungs operate as a what?

Pump.

The diaphragm.

A big, thin set of muscles that separates your thorax from your abdomen.

What are the two portions of the digestive system?

Conducting zone and the respiratory zone.

The conducting zone

The upper part of the respiratory system. It includes the nose, nasal cavity, pharynx, trachea, mouth, larynx, and lungs.

The respiratory zone

The lower part of the respiratory system. It includes the bronchioles, alveolar ducts, and alveoli.

What is mitosis?

Cell division. It allows the cell with 46 chromosomes to split into an identical cell with 46 chromosomes.

How long does mitosis take place?

Your lifetime.

How many cells are we made up of?

Trillions of cells.

The nucleus contains all of the instructions for what?

Cell replication.

How many chromosomes do we have?

46.

What are the 4 phases of mitosis?

Prophase, metaphase (longest phase of mitosis), anaphase, telophase.

What is interphase?

When cells hang out and are at work. It is not a stage of mitosis.

What happens during interphase?

DNA replicates itself.

What Greek work did mitosis get its name from?

Thread.

Who discovered mitosis?

Walter Fleming.

Daughter cells are what?

clones/copies of the original cell.

When the cell does not divide correctly, it is considered a what?

A damaged cell.

Most damaged cells will do what?

They will die out or stop replicating.

What most likely happens when a cell replicates itself and is damaged?

It destroys itself.

What happens if damaged cells do not recognize the mutation?

The damaged cell with replicate through the process of mitosis.

What might the defect in the damaged cell do?

Prevent the cell from destroying itself and thus the defective cell is duplicated.

When the damaged cell begins to replicate itself, it is known as what?

A neoplasm.

When the body of damaged cells becomes large enough it becomes a what?

A tumor.

Some tumors are what, meaning they are harmless and not growing anymore?

benign.

Diabetes is a disease caused by what?

Dysfunctional cells.

Cells in the pancreas usually produce what?

Insulin.

With type 1 diabetes, cells are unable to produce what?

They are unable to produce insulin.

With type 2 diabetes, the body does respond to what?

The body responds to insulin.