Psych 109 - Intro to Anatomy and Brain Function

Block 3

CNS

Brain and spinal cord

Somatic Nervous System (PNS)

Comprised of afferent, efferent and cranial nerves

Afferent nerves

Transmits sensory information from the organs to the brain and spinal cord

Efferent nerves

Transmits motor information from the brain and spinal cord to effectors

Cranial nerves

Controls movement and carries sensations from the head and neck; regulates glandular secretions and visceral functions. There are 12 pairs with different functions and enter+exit from the hindbrain

Autonomic Nervous System (PNS)

Regulates viscera (organs requiring automatic process) such as the heart, lungs, blood vessels, digestion and sex organs

Left hemisphere

Language dominant — processing languages and Broca’s+Wernick’s areas

Right hemisphere

Spatial awareness

Three major parts of the brain

Hindbrain, Midbrain, Forebrain

Parts of the hindbrain

Pons, Medulla, Cerebellum

Pons

Conscious arousal (alertness/awakeness)

Relays sensory information between the cerebellum, cerebrum and other parts of the brain

Regulates respiration and plays a large role in sleeping and dreaming (shuts down voluntary muscles)

Medulla

Regulates heart rate, blood pressure and respiration

Vomiting, defecation and swallowing reflexes

Plays a larger role in simple animals — crawling and swimming movements in fish for example

Cerebellum

Body balance and movement — is aware of what every part of the body is doing/intends on doing via information from the frontal lobes. Moves eyes to prevent feeling dizzy when moving head around.

May play a role in learning new movement skills like riding a bike.

Very well developed in humans and primates.

Midbrain

Basic handling in auditory and visual stimuli in humans, more important in animals.

Controls behaviours used in sexual behaviour

Behaviours/functions that were originally controlled by the midbrain in humans eventually shifted to other parts of the brain, leading the midbrain to shrink over time

Parts of the forebrain

Cortex (gyrus and sulcus), thalamus, hypothalamus, basal ganglia. limbic system

Cortex

Most important for phyisological functions like language and thinking

Outer shell of the brain

Accounts for about 80% of brain volume in humans, more than 50% in primates/complex mammals

Is about 2-3mm thick, made possible via convolutions (about 2 feet if laid out flat)

Tasks performed by limbic system/midbrain in non-mammals are performed by mammalian cortexes

Considered to be the part of the brain that makes us human — sophisticated skills such as tool making

Gyrus

Functional part of the brain that looks like a ‘ridge’ — precentral (generates signals required for voluntary movement) and postcentral (sensory information) gyri.

Creates larger brain area/surface

Sulcus

Groove between ridges that are also known as fissures; no physiological function (landmarks).

Central sulcus: separates frontal and parietal lobes

Lateral sulcus: separates frontal and parietal lobes from temporal lobe

Meninges

Outside layers that support/protect the brain and spinal cord (CNS)

Dura: outer layer, very durable

Arachnoid: resembles spider’s web and is flimsy

Pia mater: closest to the cerebral cortex

Thalamus

Takes in sensory infromation from sensory organs, analyses this and passes results to primary sensory cortex

All sense except for smell which goes to olfactory bulb

Hypothalamus

Homeostasis, species typical behaviour (ie. feeding, drinking, regulating body temperature and sex/procreation), controls most autonomic nervous system activity

The Four F’s

Parathyroid gland, thyroid gland, pituitary gland and hypothalamus

Basal ganglia

Regulation and smoothing of movements

Parkinson’s disease, Huntington’s disease, Foreign accent syndrome

Limbic system

Amygdala: gives rise to the ability to interpret negative facial expressions; some patients with damage to this part of the brain don’t feel fear

Hippocampus: memory (bilateral damage to this part of the brain causes severe memory problem)

Four lobes of the cerebral cortex

Occipital lobe, Paretial lobe, Temporal lobe and Frontal lobe

Occipital lobe — back of the brain

Processes visual information/environment via the thalamus

Parietal lobe — top of the head

Spatial perception and receives skin sensory information, houses the postcentral gyrus (behind the central sulcus)

Temporal lobe — sides of the head (L and R lobes)

Plays a role in memory and receiving auditory information; primary olfactory bulb (smells ‘triggering’ a memory is caused by the temporal lobe and limbic system)

Frontal lobe — front of head

Responsible for motor planning and output

The precentral gyrus maps basic movements of different body parts

Primary areas: basic input (sensory) + output (motor); receives information from other areas and pushes it on to other parts of the brain

Association: elaboration (making sense of your senses) and higher functions (ie. perceiving, learning and planning, etc.)

Frontal lobe primary motor area

Mild electric currents applied to parts of the primary (motor) cortex in animals – found that specific areas stimulated led to specific effects 

Evidence of contralateral control (operates in all nervous systems) – left hemisphere controls right side of body, right hemisphere controls left side of body

Brodmann areas

Homunculus

Little freak.

Something about how each enlarged body part represents how much of the brain is dedicated to receiving sensory information from it ie. hands, lips, genitalia, etc.