Coordination and Response

Homeostasis

Maintaining a stable internal environment to both internal and external conditions

Fill in the blanks: The body detects a _______ (change) then responds to it via either of the 2 _______ _______

The first system is the _______ system: the brain sends _______ _______ across the body. This system carries out _______ but _______-term changes
The second system is the _______ system: glands release _______ into the _______. This system carries out _______ but _______-term changes

The body detects a stimulus (change) then responds to it via either of the 2 control systems

The first system is the nervous system: the brain sends nervous impulses across the body. This system carries out fast but short-term changes
The second system is the endocrine system: glands release hormones into the bloodstream. This system carries out slow but long-term changes

Explain the function of Receptors, Coordination Centres, and Effectors

Receptors: Detect the stimulus

Coordination Centres: Receive information about the stimulus and coordinate a response

Effectors: Organs or glands that carry out the change conducted by the coordination centre

The nervous system is made up from two smaller systems. Name them and explain the difference between them

The nervous system is made up from the Peripheral Nervous System (PNS) which includes the nerves throughout the body, and the Central Nervous System (CNS) which includes the brain and spinal cord

Nerves consist of neurons (nerve cells) that transmit the fast electrical impulses. Name labels 1-8 and explain all of them, but 3, 4, 7, and 8

1. Cell Body; Contains the main organelles

2. Dendrites: Branches of cytoplasm. The extended axon and dendrites help connect the cell to other neurons for the message to travel

3. Nerve Endings

4. Cytoplasm

5. Axon: Extended cytoplasm

6. Myelin Sheath: Insulates the impulses to make them travel faster and more efficiently

7. Cell Membrane

8. Nucleus

The Nervous System can perform voluntary (fully aware) and involuntary (no control over them) actions. Explain how the voluntary action works

1. Receptors detect the stimuli and send info to the brain via sensory neurons

2. The brain coordinates the response via the motor neurons which are connected to effector cells

3. The relay neurons (found in the CNS) connects the sensory to the motor neuron

Fill in the blanks: Between each neuron there is a _______ (gap) which cannot be crossed by _______ _______

When the _______ arrives at the gap, it release a chemical - _______ - these cross the synapse by _______. The _______ then regenerates the _______

Between each neuron there is a synapse (gap) which cannot be crossed by electrical impulses

When the impulse arrives at the gap, it release a chemical - neurotransmitters - these cross the synapse by diffusion. The neurotransmitters then regenerates the impulse

Reflexes are involuntary, rapid, and automatic responses - they travel in a nerve pathway called the Reflex Arc. Name labels 1-8

1. Receptor

2. Grey Matter

3. Intermediate/Relay Neuron

4. White Matter

5. Synapse

6. Motor Neuron

7. Effector

8. Sensory Neuron

The CNS is protected. What protects the brain and the spinal cord

The cranium protects the brain

The vertebral column protects the spinal cord

This is a diagram of the brain. Name labels 1-6, and explain the function of all, but 6

1. Hypothalamus: Involved in homeostasis

2. Pituitary (Master) Gland: Regulates many body functions

3. Medulla (Oblongata): Controls unconscious activities (e.g. breathing)

4. Cerebellum: Responsible for muscle coordination and movement

5. Cerebral Cortex: Responsible for consciousness, memory, intelligence, and language

6. Spinal Cord

Hormones

Chemical messengers secreted by glands in the body that regulate and coordinate various processes

What is the function of the blood in the endocrine system

The blood carries the hormones from the gland that secret them to the target destination through the bloodstream

This is the main endocrine system. Name labels 1-5, state the hormone each gland secretes and why

1. Thyroid Gland: Secretes thyroxine which controls metabolic rate and affects growth

2. Adrenal Gland: Secretes adrenaline for a fight or flight response

3. Pancreas: Secretes insulin and glucagon to regulate blood glucose levels

4. Ovaries: Secrete oestrogen and progesterone for sexual development

5. Testicles: Secrete testosterone for sexual development

State all 5 hormones that the pituitary (master) gland releases

1. Growth Hormones - Control growth

2. Thyroid-Stimulating Hormone - Stimulates the thyroid gland to secrete thyroxine

3. Follicle-Stimulating Hormone - Develops follicles in ovaries and increase sperm production

4. Luteinising Hormone - Stimulates ovulation and testosterone release

5. Anti-Diuretic Hormone - Causes kidneys to reabsorb water

Explain how Blood Glucose level regulation occurs

When the blood sugar levels are low, the pancreas secretes glucagon hormone which converts stored glycogen to glucose to increase the blood sugar levels

Alternatively, when the blood sugar levels are high, the pancreas secretes insulin hormone which stores the excess glucose to glycogen to decrease the blood sugar levels

This is a negative feedback mechanism

The conversion between glycogen and glucose occurs in the liver - the job of the pancreas is to release hormones

Negative Feedback

Negative feedback works to oppose something to restore homeostasis. For example, when the body temperature is too high, the body cools itself down by setting itself a low temperature