The nervous and endocrine system study guide

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The two systems that control and coordinate the human body

Nervous and Endocrine Systems

The Nervous System is responsible for (speed)

Rapid, specific and short term responses to stimuli.

The Nervous System is composed of two smaller systems, known as

The Central Nervous System (CNS) and Peripheral Nervous System (PNS)

The Central Nervous System is composed of the

Brain and Spinal Cord

The Peripheral Nervous System is composed of the

Nerves that branch out from the brain and spinal cord; The rest of the nervous system that isn’t the brain or spinal cord.

What does the peripheral nervous system do?

It carries information to and from the CNS.

What is the PNS made up of?

It is made up of Motor and Sensory Nerves.

What does the CNS do?

It receives, processes and responds to information from PNS.

What are neurons?

They are specialised cells that carry information in the form of an electrical impulse

What are nerves?

They are bundles, or fibres of neurons that communicates through electrical impulses.

What are dendrites in a neuron?

They are tree like structures that receives electron impulses from other neurons.

What is the cell body (soma) in a neuron do?

It contains the neuron’s key organelles, contains its DNA, gives it structure and controls the cell.

What does the Nucleus in a neuron do?

Is the “control centre” of the cell that specialises in regulating its function, reproduction and houses its DNA .

What does the axon terminal in a neuron do?

It houses the synapses, which sends electrical impulses or signals to other neurons.

What does the Node of Ranvier do in a neuron?

It allows ions to diffuse in and out to speed up electrical conduction, they function as repeaters that propagate or regenerate the action potential over and over; they are the gaps between/along the myelin sheath.

What is is the axon in a neuron?

It is a portion of the neuron that carries the electrical impulse away from the cell body, to the axon terminals. It contains the myelin sheath and node of ranvier.

What does the myelin sheath do in a neuron?

It insulates the axons for faster and more efficient signalling.

What is the synapse in a neuron?

It is the end of a neuron that connects and communicates to another neuron’s cell body via synapses that release neurotransmitters in the axon terminal. This is then sent to the dendrite of a receiving neuron.

What is the correct order of the stimulus response model?

Stimulus ⟶ Receptor ⟶ Control Centre ⟶ Effector ⟶ Response.

What is the stimulus response model?

It is a model which describes how organisms respond to changes in their environment and respond accordingly.

What is a motor neuron?

A neuron that carries signals away from the CNS, to effectors.

What is a sensory neuron?

A neuron that carries signals to the CNS.

What is an Interneuron/Relay neuron?

A neuron that acts like a middleman between neurons that connects neurons together and sends signals to other neurons, such as other interneurons or motor neurons, or receive signals from sensory or other interneurons. They can also process stimuli, especially in reflex arcs. They are specific to the CNS.

What is an effector?

It is a muscle or gland that is acted upon by a motor neuron in response to a stimulus.

What is a receptor?

It is a structure (usually a cell or organ) that detects stimuli.

What is a reflex?

They are immediate, involuntary responses to a stimulus.

What is an example of a reflex?

Blinking, salivating, knee-jerk, pupil dilation.

What is the process of a reflex arc?

Receptor → Sensory Neuron → CNS (Spinal cord) → Motor Neuron → Effector

What part of the CNS processes a stimulus in a reflex arc?

The spinal cord

Which of the following is a voluntary action?

Running, jumping, walking, swimming.

Which of the following are involuntary actions?

Breathing, heartbeat, salivating, blinking.

What is the endocrine system?

It is a system that controls and coordinates the body through chemical messengers known as hormones.

What is the difference between the endocrine system and the nervous system?

The endocrine system is much slower, is transported through the bloodstream, lasts longer and is more generalised. The Nervous system is fast, rapid, and specific.

What are the types of organs that comprise the endocrine system?

Glands - they secrete hormones.

What are hormones?

Hormones are chemical messengers that travel via the bloodstream.

What do hormones do?

They travel and bind to receptors/glycoproteins or target cells to induce a response or change to that cell.

What are the receptors on target cells also called?

Glycoproteins

Which of the following are hormones?

Insulin, glucagon, testosterone, oestrogen.

How do hormones bind to receptors?

Receptors have specific shapes that match up ONLY to a specific hormone that is compatible with it.

How are hormones transported?

They are transported via the bloodsteam.

What is negative feedback?

It is when a response goes in the opposite direction of a stimulus, and it works until the stimulus has decreased.

What is positive feedback?

It is when a stimulus is amplified, forcing the organ out of homeostasis; the response goes in the direction of the stimulus.

What is an example of negative feedback?

Sweating during hot temperatures - cooling yourself down.

What is an example of positive feedback?

Childbirth, baby pushes against cervix, and the body secretes oxytocin to induce contractions to push the baby out.

What are the five main receptors?

Chemoreceptor, Thermoreceptor, Mechanoreceptor, Photoreceptor, Pain receptor (Nociceptor),

What gland produces adrenaline?

The adrenal gland.

What does adrenaline do?

Induces “Fight or Flight” state, increases heart and breathing rate, dilates airways and contracts blood vessels.

When is adrenaline triggered and by what?

Adrenaline is produced during stressful or dangerous events, by the sympathetic nervous system.

What are catalysts?

Catalysts are substances that are added to a reaction to increase the reaction rate. (without being consumed in the process) It was allowed for more efficient and faster processes by using less energy.

What are enzymes?

Enzymes are biological catalysts that speeds up reactions in our bodies.

How do enzymes work?

They work by binding to SPECIFIC substrates to be activated, and they can be reused.

An example of enzymes is?

Lactase (breaks down lactose sugars in milk), amylase (breaks down food in the mouth.)

What is denaturing?

It is the process of changing an enzyme structure, making it so that it cannot fit into their respective substrates.

What is the main cause of denaturing?

Changes from optimal temperature and ph.

What is homeostasis?

It is characterised by maintaining a constable, stable internal environment whilst adapting to external changes.

What is the process of homeostasis? (stimulus response model)

Receptor ⟶ Control Centre ⟶ Effector ⟶ Homeostasis

Is homeostasis maintained by negative or positive feedback?

Negative feedback.

What happens when blood sugar levels are increased?

Insulin is secreted by the pancreas to lower blood sugar levels in the body.

What happens when blood sugar levels are decreased?

Glucagon is secreted by the pancreas to increase blood sugar levels in the body.

What happens when our body temperature increases?

We start to sweat and our blood vessels start to dilate

What happens when our body temperature decreases?

We shiver, our metabolism is increased, and our blood vessels at our extremities contract to preserve heat.

What is another word for electrical impulse?

Action potential

What happens when blood sugar gets too high?

Our blood thickens and moves much slower.

What happens when blood sugar gets too low?

We get dizzy, irritable, and light headed.