Homeostasis
Name 1 thing that is regulated in the human body.
Can be:
Temperature, blood glucose levels, water levels, salt ion levels.
Name the three types of neurons.
Sensory neurons, interneurons, motor neurons (SIM)
How are hormones transported around the body?
Through the bloodstream
Is basking a temperature regulation process typical of endotherms or ectotherms?
Ectotherm
What are temperature receptors known as?
Thermoreceptors
What are the stages of the stimulus-response model?
Stimulus - Receptor - Control Centre - Effector - Response
What is a neurotransmitter?
A neurotransmitter is a specialised messenger chemical that transfers or sends information from one neuron to another or to a gland or muscle.
What is a hormone?
CHEMICAL MESSENGER THAT IS SENT OUT BY AN ENDOCRINE GLAND TO A TARGET CELL
What is the difference between endotherms and ectotherms?
Endotherms are able to regulate their body temperature internally by metabolic processes, keeping it relatively constant regardless of the external environment. Ectotherms rely on external sources of heat to regulate their body temperature, so it often changes with the surrounding environment.
Name an example of an endotherm and an example of an ectotherm.
Endotherm: humans, birds
Ectotherm: reptiles, amphibians
What is homeostasis?
The ability of the body to maintain a stable internal environment.
In what direction does a nerve impulse travel down a neuron?
From the dendrites, along the axon, to the axon terminals.
What are target cells?
The cells affected by specific hormones.
What is the control centre for the temperature stimulus-response model?
Hypothalamus (brain)
What is the function of the myelin sheath?
Acts as insulation for the neural impulse, allowing for fast electrochemical transmission along the axon, reducing interference between other neurons.
Why is homeostasis important?
Homeostasis is essential to survival because the internal environment needs to be stable to provide the narrow range of optimal conditions for the cells of the body to operate best.
What is the difference between a sensory neuron, interneuron and sensory neuron?
SENSORY NEURONS SEND MESSAGES FROM SENSORY RECEPTORS AROUND THE BODY TO THE CNS (BODY TO BRAIN)
Interneurons provide the connection between the sensory and motor parts of the nervous system.
MOTOR NEURONS SEND MESSAGES FROM THE CNS TO THE EFFECTORS (BRAIN TO BODY)
The nervous system and endocrine system are linked by what structure?
The hypothalamus
What is vasoconstriction?
Blood vessels constrict (become narrow) to reduce blood flow to the skin and retain heat in the body.
What is hydrotropism?
A plant’s growth response to moisture, where roots grow towards areas with higher water concentration.
What is negative feedback?
A mechanism that operates by sensing when a system deviates from a set point, and then activating responses to counteract the deviation and bring the system back to its set point.
Explain how a reflex works (the process) and why it is needed.
Involves a sensory receptor, sensory neurons, interneurons in the spinal cord, motor neurons and an effector such as a gland or muscle.
It is an automatic response to a stimulus. A reflex does not immediately include the brain. Messages go to the spinal and back out. This lets us respond instantly to the environment.
Explain the action of hormones (simplified to 3 steps).
1. cell in endocrine gland secretes hormones
2. hormones travel in the bloodstream
3. hormone reaches the target cell
Describe the negative feedback mechanisms (response) that occur when the body’s temperature increases.
The skins blood vessels dilate, increasing blood flow to the skin’s surface, and allowing heat to be released to the environment. Sweat glands also produce sweat, which evaporates and helps to cool the skin.
Compare the type of signal, signal transmission, signal speed, and response time of the nervous system and endocrine system.
NS: Electrical impulses and neurotransmitters, neurons, fast, short-lived.
ES: Hormones, bloodstream, slow, longer-lasting.