chemistry of living things context 2

Internal Systems Allowing Life

• Cellular respiration

  • Glucose + Oxygen -> Carbon Dioxide + Water + Energy (ATP)

• Humans:

  • Digestion:

    • Function: Breaks down food into nutrients to be transported to cells

      • Ingest

      • Break food down

      • Eliminate what can’t be ingested

    • Nutrients: glucose (help atp), amino acids (help enzymes, proteins), fatty acids (long term energy), vitamins (metabolic processes), minerals (functions)

    • Absorbed into bloodstream thru the walls of the intestines so they can be transported to cells

    • Use glucose in cellular respiration to produce ATP

  • Respiratory system

    • Function: gas exchange of oxygen & carbon dioxide

    • Oxygen is inhaled into the lungs and the alveoli

    • Alveoli transfer oxygen to the capillaries

    • Use oxygen in cellular respiration to produce ATP

    • Expels carbon dioxide in cellular respiration and transported to lungs

  • circulatory system

    • Function: to transport oxygen, nutrients, hormones, glucose… to cells while also removing waste products

    • Cellular respiration: transports oxygen and glucose to cells and carbon dioxide out of cells

  • Excretory system

    • Function: Removes wastes from the body

    • Cellular respiration: expels water and carbon dioxide

      • Gas exchange - carbon dioxide

      • Kidneys regulate balance of water by filtering water from blood and expelling as urine

• Plants

  • Photosynthesis

    • Energy (sunlight) + Carbon Dioxide + Water -> Glucose + Oxygen

  • Cellular Respiration

Control Systems: Nervous & Endocrine

Nervous System

• Function: Network of cells of Neurons that send electrochemical messages around the body rapidly allowing us to react to changes in surroundings and respond to them

• Stimulus: Any internal or external change in the environment

• Receptors: group of specialised cells that detect stimuli

  • Stimuli detections converted into electrical impulses

  • Located in sense organs

• Coordinator: when receptor stimulated, sends signal along the neurons to brain

  • CNS (central nervous system) = brain + spinal cord

  • Brain then coordinates response

• Effectors: part of the body that produces the response

• Conscious Responses: the change in the body

• Stimulus -> receptor -> Coordinator -> Effector -> Response

• Reflex Responses: 

  • Involuntary action

  • A nerve impulse taking a short-cut to the spinal cord and back

  • Super fast response to a stimulus - usually a response to danger

  • eg; touching something hot, arm moves away from hot object

• Reflex Arc

  • Receptor detect stimulus

  • Sensory neuron sends signal to relay neuron

  • Motor Neuron send signal to effector

  • Effector produces response

• Parts of Neauron:

• Dendrites

  • Receive signals from other neuron cells

• Cell Body

  • Contains cell nucleus

• Nucleus

  • Contains the genetic material (chromosomes) of the neuron cell

• Axon

  • Conducts electrical impulses along the neuron cell

• Myelin Sheath

  • Insulates the axon to help protect the neuron cell & speed up transmission of electrical impulses

• Axon Terminal 

  • Transmits electrical & chemical signals to other neuron cells & effector cells

Endocrine System

• Function: Collection of glands that release hormones (chemical messages) to transfer info around the body

  • Hormones provide slower messages than the nervous system, buy they occur over a longer period of time

  • Hormones control processes in the body eg; storage, release of glucose into the blood, growth, water balance, reproduction…

  • Glands work together but are not controlled from one central location

  • Hormones travel in the blood and only target particular cells respond to each hormone - many substances 

• Homeostasis: constant conditions - the maintenance of constant internal conditions in an organism

• Negative feedback: type of control that is found in homeostasis - responds when conditions change

• Stimulus reaction: Chemical internal changes that brings a slow but long lasting response 

Interactions

• Stress response: Nervous system initiates fight or flight response and then endocrine system release hormones for a reaction

• Both control reactions and responses