Introduction to the brain

Question 1

What are the functions of the brain?

Answer 1

1) use sensory input to guide movement

2) use sensory input to regulate internal organs

Question 2

What are the bumps and rigids in the cortex?

Answer 2

Gyrus

Question 3

What are the folds and calleys in the cortex?

Answer 3

Sulcus

Question 4

What are the 3 main parts of the brain?

Answer 4

Forebrain, midbrain, hindbrain

Question 5

What does the forebrain use?

Answer 5

current sensory input and past experience to make (and communicate) decisions

Question 6

What does the midbrain use?

Answer 6

current sensory input to direct movement

Question 7

what does the hindbrain use?

Answer 7

maintains the current state; controls mouth

Question 8

how are messages sent through the nervous system?

Answer 8

uses electrical signals. Messages are sent rapidly but the communication is costly.
Network structure determines which cells receive the messages

Question 9

How are messages sense through the vascular system?

Answer 9

Through chemical signals (hormones).
Messages are sent more slowly but the communication is cheap.
Membrane receptors determine which cells receive the messages

Question 10

Why are both the vascular system and nervous system used for communicating

Answer 10

We have two ways of communicating because sometimes the vascular system is not quick enough (e.g. someone about to hit you wouldn’t be responded to fast enough). We can’t just have the nervous system as it is much costlier. This is a cost-benefit trade off.

Question 11

Order of animals existing?

Answer 11

Prokaryotic cells, eukaryotic cells, metazoa, bilateria, chordates, vertebrates, jawed fishes, mammals, primates, homo

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Question 12

Characteristics of prokaryotic cells

Answer 12

Membrane produces energy

DNA regulates protein

Question 13

Characteristics of eukaryotic cells

Answer 13

Energy production is no longer in the cell membrane but now the mitochondria.

Cell membrane performs phagocytosis

Question 14

Phagocytosis

Answer 14

white blood cell engulfs bacterium

Question 15

Characteristics of metazoa

Answer 15

After divisions, cells are now able to stick together to form a multicellularity. Cell division. Different cells can focus on different functions.
Get a digestive chamber within the cell for more efficient use of energy.

Question 16

What is multicellular

Answer 16

of an organism or part) having or consisting of many cells.

Question 17

What is bilateria

Answer 17

The appearance of the bilateria are the first to have bilateral symmetry. They have a proper front, back, left and right. Bilateria are our direct ancestors. Prior to this there was radial symmetry (like we see now in jelly fish). Now we have bilateral symmetry which means the mouth and anus are completely separate (as shown in the right picture). The right end of the body shows the start of the brain. This has the first appearance of muscle

Question 18

What characteristcs are there of chordates

Answer 18

After cambrian explosion.

Chordates had a stiffened rod and a recognisable tail. This is the beginning of a spinal cord

Question 19

Characteristics of a jawed fish

Answer 19

First organisms to have teeth meaning they can catch and eat food more easily. This makes them more efficient and become bigger and put more energy into the brain. They can also move their eyes separate to the rest of their body. They can maintain a gaze on a prey item. The cerebellum appears here

Question 20

characteristics of mammals

Answer 20

The key innovations here are differentiated teeth (e.g. a horse vs cat have different teeth such as enlarged canines in cats).
Mammals here tended to be insectivorous.
Primates emerged from this.

Question 21

characteristics of homo

Answer 21

Changes of hands and teeth changed before the volume of cerebral cortex increased.

Question 22

Why do teleost fish have a large optic tectum?

Answer 22

have a good sense of sight

Question 23

Why do mammals have a large olfactory bulb?

Answer 23

good sense of smell

Question 24

Why do platypus have a large bill

Answer 24

to sense through electrical perception where its prey is. A huge part of its cortex is dedicated to this perception. The bill is full of sensitive regions.

Question 25

Key points

Answer 25

• The brain sends messages to body via nervous system (electrical signals; quick/costly) and vascular system (hormones; slow/cheap)
• The brain can be subdivided into regions that are (loosely) associated with particular functions
• The brains of humans and other vertebrates share a similar gross structure
• The relative size of different brain areas indicates the functional specialisations of the animal, reflecting its ecology
• Several of the major evolutionary changes in the brain were linked to changes in motor control and digestive efficiency