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Today, in our biology class we learnt about the endocrine system. We had to do some activities and we did it in groups.

1. Hormones are chemical substances that help to regulate processes in the body.
2. Glands that secrete hormones:

3. Effects of Adrenaline: Prepares body for action – ‘fight or flight’.

Adrenaline is the hormone secreted in ‘fight or flight’ situations. It’s secreted when you are frightened, excited or keyed up. Adrenaline effects could be: increased breathing, increased pulse rate, widened pupils, increased blood glucose concentration and increased pulse rate. These people are secreting adrenaline since they are in an exciting situation in which they have to act quickly.

In Biology we studied DRUGS.

a) Here is a webpage to revise on the topic. Then this is a test to check my knowledge.

b) Antibiotics work by damaging the cell wall of bacteria.

In Biology we are studying the eye as a sense organ. Male gave us some activities to do in pairs. I was with Luna.

1. Structure of the eye.

2.  Functions of the eye structures.

3. Booklet page 9 exercise 3. 

4. Animation showing how the eye works.  

5. Booklet page 9 exercise 2: The cornea bends or refracts the light rays for the lens to bend and focus them on the fovea (if there is a bright light, on cones) or throughout the retina (if there is dim light, on rods).

6. VIDEO explaining the pupil reflex.

-stimulus: a bright light. >> receptor: cones >> coordinator: brain >> effector: radial and circular muscles >> effect: circular muscles contract while radium relax >> response: the pupil constricts.

-stimulus: a dim light. >> receptor: rods >> coordinator: brain >> effector: radial and circular muscles >> effect: circular muscles relax while radium contract >> response: the pupil gets dilated.

CIRCULAR MUSCLE vs RADIUM MUSCLE: Antagonistic muscles

7. Booklet page 9 exercise 1c: In the dark room light is focused all over the retina, where the rodes are. Rodes are stimulated the, but rodes are of black and white vision only. So Jasmin seed only shapes, not colours.

8. Animations to learn how the eye focuses on a nearby and a distant object.

9. Booklet page 9 exercise 2b: If a close object is focused, the light rays coming will be diverging so they will need a lot of bending. The cornea will bend them and focus them on the lens and the lens will need to be thick so it bends more. The ciliary muscles contract, the suspensory ligaments go slack and the lens becomes shorter and fatter.

Booklet page 10 exercise 4a: Lens and cornea

10.  Booklet page 10 exercise 5: 

a. light receptors bring out electrical impulses.

In Biology we started working with the Nervous System. Here is anentry on Male´s blog with a few interactive activities and videos.

Activities:

1.a. Key Parts of the Control Center; The Receptors; The neurons and nerve cells;

b. 

Sensory Neuron: transmits nerve impulses from receptors to coordinators.

Relay Neuron: Transmits nerve impulses from Sensory Neurons to Motor Neurones.

Motor Neurones: Transmits nerve impulses from the central nervous system (brain &  spinal cord) to effector nerve cells.

c. Reflex Action:

Stimulous >> recept cells >> coordinators (CNS) >> effector cells

d. Synapse:

A synapse is what happens when chemical signals pass from one cell to another. It occurs in the synaptic cleft, which is the tiny gap between the pre-synaptic neuron and the post-synaptic neuron.
Every pre-synaptic neuron has vesicles inside, near the pre-synaptic membrane. Each vesicle contains thousands of neurotransmitters. When the pre-synaptic neuron gets “excited” by an axon potential it’s vesicles diffuse through the cell membrane and release their content into the  synaptic cleft.
Following, the tiny receptors of the post-synaptic neuron interact with the neurotransmitters. These ones bind into the receptors and cause an action as result. Likelihood can be increased and the cell becomes activated firing an action potential or it can be decreased.
Finally, the neurotransmitters molecules left in the synaptic gapdrift away by diffusion, or go back to the vesicles to be reused by a process called re-uptake, or are broken down by enzymes and component parts go back to the pre-synaptic neuron.