The Human Brain and Nervous System - bio week 2 Flashcards
What is the NS divided into
The CNS - brain and spinal cord
The Peripheral nervous system PNS - the nerves and the sensory organs
What are the anatomical directions?
Front - anterior
Back - posterior
Top - dorsal
Back - ventral
Structures toward the middle are medial
Structures towards the outside are lateral.
what is a Neuron?
Where are they located?
What are the different types?
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
what are the divisions of the PNS?
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
what is the Somatic NS?
comes into contact with the external environment, conveys from sensory detectors to the brain and controls movement.
what is the Autonomic NS?
internal environment: regulates internal functioning e.g. digestion, respiration, circulation, excretion and secretion of sex hormones
Sympathetic vs Parasympathetic NS
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
Afferent verves vs Efferent nerves?
Afferent - Arriving - sensory into towards the CNS
Efferent - exiting - motor signals away from CNS
what is the sulci and gyri of the brain?
sulci - clefts when deep enough to separated 2 features, called a fissure
Gyri - folds
what is the cerebrum involved in?
more complex and adaptive processes - learning, motivation, memory etc
What is the brain stem linked with?
activities for survival
problems with a big brain?
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.
How does the human brain develop?
Development of the neural tube in the womb forms 3 swellings: the forebrain, midbrain and hindbrain
These develop into 5 major divisions.
what are the divisions of the hindbrain?
- Myelencephalon
Medulla -controls basic functioning, (e.g. breathing, heart rate) and also involved in reflex responses. - Metencephalon
- Cerebellum- (‘little brain’) - involved in the development and co-ordination of movement.
- Pons- (‘bridge’) - regions involved in motor control and sensory analysis.
Midbrain division?
- 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.
What are the divisions of the forebrain?
- Diencephalon
- Telencephalon
what does the Diencephalon of the forebrain do?
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
what does the Telencephalon of the forebrain do?
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
Frontal lobe of cerebral cortex function?
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.
occipital lobe?
Involved in the initial visual reception (primary visual cortex), which it then passes to the temporal and parietal lobes.
Parietal lobe
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).
Temporal lobe
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.
