The Human Brain and Nervous System - bio week 2

Question 1

What is the NS divided into

Answer 1

The CNS - brain and spinal cord
The Peripheral nervous system PNS - the nerves and the sensory organs

Question 2

What are the anatomical directions?

Answer 2

Front - anterior
Back - posterior
Top - dorsal
Back - ventral

Structures toward the middle are medial
Structures towards the outside are lateral.

Question 3

what is a Neuron?
Where are they located?
What are the different types?

Answer 3

Basic unit of structure and function in the nervous system (NS).
They are located in the CNS & PNS.
Sensory – respond to external stimuli, transmit sensory info to CNS (Afferent = Arriving)

Motor - carry messengers from CNS to muscles and glands. (efferent = exiting)

Interneurons - transmit messages to other neurons

Question 4

what are the divisions of the PNS?

Answer 4

The Somatic nervous system and the Autonomic nervous system
These are both comprised of Afferent and Efferent nerves.
In the Efferent nerves of the Autonomic NS there is the Sympathetic NS and the Parasympathetic NS

Question 5

what is the Somatic NS?

Answer 5

comes into contact with the external environment, conveys from sensory detectors to the brain and controls movement.

Question 6

what is the Autonomic NS?

Answer 6

internal environment: regulates internal functioning e.g. digestion, respiration, circulation, excretion and secretion of sex hormones

Question 7

Sympathetic vs Parasympathetic NS

Answer 7

Sympathetic – activated by conditions that promote arousal, e.g. increase heart rate, energy. Expenditure - fight or flight

Parasympathetic – activated by conditions of recovery e.g. decrease heart rate, energy conservation - rest and digest system

Question 8

Afferent verves vs Efferent nerves?

Answer 8

Afferent - Arriving - sensory into towards the CNS
Efferent - exiting - motor signals away from CNS

Question 9

what is the sulci and gyri of the brain?

Answer 9

sulci - clefts when deep enough to separated 2 features, called a fissure
Gyri - folds

Question 10

what is the cerebrum involved in?

Answer 10

more complex and adaptive processes - learning, motivation, memory etc

Question 11

What is the brain stem linked with?

Answer 11

activities for survival

Question 12

problems with a big brain?

Answer 12

Human brain 6x larger than expected for body size.
Bigger brain requires a greater quality and quantity of nourishment – started eating meat 2m years ago

Harder to give birth with a larger head. The brain continues to develop after birth. Humans are, by brain standards, premature.

Question 13

How does the human brain develop?

Answer 13

Development of the neural tube in the womb forms 3 swellings: the forebrain, midbrain and hindbrain
These develop into 5 major divisions.

Question 14

what are the divisions of the hindbrain?

Answer 14

1. Myelencephalon
   Medulla -controls basic functioning, (e.g. breathing, heart rate) and also involved in reflex responses.
2. Metencephalon
   - Cerebellum- (‘little brain’) - involved in the development and co-ordination of movement.
   - Pons- (‘bridge’) - regions involved in motor control and sensory analysis.

Question 15

Midbrain division?

Answer 15

3. Mesencephalon

Tectum - relays visual and auditory information
Superior colliculus – visual info.
Inferior colliculus – auditory info

Tegmentum
Substantia Nigra – movement and reward
Red Nucleus - basic body movements
Reticular Formation – controls consciousness and arousal, sleep and motor functions.

Question 16

What are the divisions of the forebrain?

Answer 16

1. Diencephalon
2. Telencephalon

Question 17

what does the Diencephalon of the forebrain do?

Answer 17

Epithalamus - contains pineal gland which secretes melatonin
Thalamus-” inner chamber”, relay station for sensory information transmitted to cerebral cortex
Hypothalamus - sensor for human’s basic needs. Involved in hunger, thirst, temperature regulation and sexual behaviours. Regulates the release of hormones from pituitary gland

Question 18

what does the Telencephalon of the forebrain do?

Answer 18

Limbic system – involved in emotion
Amygdala - ”Almond”, fear and anger
Cingulate gyrus - positive, negative emotions, experience of pain and attentional processes.
Hippocampus – “sea horse” involved in memory.

Basal Ganglia – involved in generation of voluntary movement, muscle tone and posture.
3 main nuclei (called striatum)
Caudate nucleus
Putamen
Globus pallidus

Striatum communicates with substantia nigra and cerebral cortex

The cerebral cortex
Layer of convoluted tissue covering 2 cerebral hemispheres
Each hemisphere divided into 4 lobes:
> frontal lobe
> Parietal lobe
> Temporal lobe
> Occipital lobe

Question 19

Frontal lobe of cerebral cortex function?

Answer 19

Posterior region – primary motor cortex involved in the control of voluntary body movements
Anterior region - prefrontal cortex complex intellectual functioning, e.g. planning and sequencing behaviours, higher thought functions, emotion regulation.

Question 20

occipital lobe?

Answer 20

Involved in the initial visual reception (primary visual cortex), which it then passes to the temporal and parietal lobes.

Question 21

Parietal lobe

Answer 21

Anterior region – somatosensory cortex processes sensory information e.g touch, pressure, temp, sensation

Posterior region - involved in complex visual processing determining where an object is (visuo-spatial attention).

Question 22

Temporal lobe

Answer 22

Core area for processing auditory information (“primary auditory cortex”) – involved in language processing, comprehension of words.

Memory functions (medial portion).

Also involved in complex visual processing - associated with determining what an object is when it is perceived visually.