Biology U1 AOS2 Systems

Cell

the smallest structural unit of living systems.

Tissue

a group of similarly composed cells that work together to perform a specialised function

Organ

a collection of different types of tissue that perform a singular function

System

group of organs that together perform a common function

Organism

collection of systems that coordinate and contribute to a common cause.

Xylem cells

Responsible or the transport of water and minerals from the roots to the leaves of the plant

Phloem cells

responsible for the transport of sugars and other nutrients throughout the plant

Heterotroph

organisms that have to consume other organisms or their products to obtain organic molecules

Organic Molecules

Molecules that provide chemical energy to the animal to be able to live, survive and reproduce

Physical Digestion

movement of organs and tissues causing the breakdown of food into smaller pieces

Chemical Digestion

enzymes and stomach acid break down food into smaller molecules that can be absorbed

Mouth

pH of 6-8. Amylase enzymes in saliva start breakdown of carbohydrates, lipase enzymes start breakdown of fats. teeth mechanically break food into smaller pieces

Oesophagus

Saliva continues to mix with food as it travels to the stomach. movement of food is aided by peristalsis

Peristalsis

muscular contractions that are involved in physical digestion

Stomach

protease enzymes begin to digest proteins, stomach membrane releases acid. pH of 1 to 3 pH. peristalsis continues to digest food

chyme

partially digested food leaving the stomach

Liver

site of bile production for the physical breakdown of fats. processes nutrients, stores excess glucose in the form of glycogen

Gall Bladder

bile is stored and further concentrated before the small intestine

Pancreas

enzymes are produced and released when chyme reaches small intestine. secrets bicarbonate, neutralising acids. regulates blood sugar levels

Small Intestine

enzymes continue the breakdown of carbohydrates and proteins, responsible for majority of fat breakdown. lining cells absorb nutrients and waste

Large Intestine

Final absorption of water, vitamins and minerals. undigested food becomes solid and compact for egestion

Signalling molecules

allow cells to communicate with each other to perform functions within the body

Pituitary Gland

A small area in the brain that regulates other glands, releases growth hormones.

Hypothalamus

A region in the brain that maintains body temperature, influences other glands

Thyroid

Gland in the neck involved in controlling growth, metabolism and development

Pancreas

Involved in functioning of the digestive system, maintains blood glucose

Adrenal Glands

involved in the body’s stress response, metabolic regulation, blood pressure, and immune system

Testes and Ovaries

Major role in developing and regulating the body’s reproductive system

Homeostasis

The maintenance of a stable internal environment despite changes in the external environment

Stimulus Response

stimulus, receptor, modulator, effector, response

Receptors

thermoreceptors, photoreceptors, chemoreceptors, nociceptors, and baroreceptors

Negative Feedback

The body’s response to stimuli in order to revert the system back to the state it was in before the stimulus occurred

Radiation

the transfer of heat via waves of light, doesn’t require physical contact

Conduction

transfer of heat through physical contact with another object

Evaporation

the loss of heat via the conversion of water from liquid to gas

Convection

the transfer of heat via movement of a liquid or gas

Endotherms

organisms that produce their own heat by metabolic processes

Glucose

the main source of energy for all cells in the body. obtained from carbohydrates

Glycogen

produced by the process of glycogenesis, stored in liver cells for prolonged periods of time and only used when needed

High Blood Glucose Response

Islets of Langerhans detect change and cause beta cells to release insulin. Glucose binds to cell receptors, which stimulates glucose receptors to be inserted into the cell’s membrane

Low Blood Glucose Response

Islet of Langerhans detect change and cause alpha cells to release glucagon. Glucagon stimulates liver cells to break down glycogen into glucose, and release this into the bloodstream

Type 1 Diabetes

The body’s immune system destroys insulin-secreting beta cells. Little to no insulin is produced, leading to unregulated blood glucose levels

Hyperthyroidism

The thyroid continually produces T3 and T4, which can lead to increased metabolism, increased blood pressure, increased heartrate, etc.

Hormone Regulation

The hypothalamus detects a change in hormone levels. The hypothalamus releases TRH. The anterior pituitary gland secretes TSH (thyroid stimulating gland). TSH stimulates the thyroid to secrete T3 and T4.