1.0 Neurobiology

Neurobiology

Physiology is the study of 

• Biological processes occurring in the body.

• Study of functions within the body & how they work.

Anatomy is the study of the

• the size, shape & location of the different bodily structures

Physiological functioning of the body is connected to

• Cognitive processes

• Emotions

• Behaviors

The biological perspective of physiology

• how psychological issues are impacted by biological processes

Physiology help psychologists to

• Identifying physiological components of mental health disorders.

• Understand the mechanism of action of psychiatric & recreative drugs.

• Incorporating neuroscience findings into evidence- based practice.

• Neurodiciplinar reserach

BIOfeedback

• Machine that gives feedback of their own mental processes → to later help them to maintain physiological processes

Homeostasis

• body’s attempt to maintain a constant internal environment, which requires constant monitoring &

adjustments as the conditions change.

Homeostatic regulation always requires 

• Receptor,

• Control/integration centre

• Effector

Components of homoestasis

• Receptor

• Control center

• Effector

Receptor

Control center

Effector

Basic operational mechanism of the components in the homoestasis

• Feedback loop

Homeostasis generally operates 

Bidirectionally

Homeostasis generally operates bidirectionally

• Respond to deviations in physiological parameters in both directions

• When they rise or fall, ensuring that they are maintained relatively constant.

CNS anatomical

• Spinal cord

• Brain

PNS anatomical

• Ganglia

• Nerves (cranial / spinal)

Functions of NS

• afferent (input from the CNS) & efferent (output from CNS)

The nervous & endocrine systems are the main 

• Responsible for regulating & maintaining homeostasis.

Functional division of the NS

• The PNS neurons can be divided according to the direction of the information

Afferent / Sensory (neuron)

• Peripheral sensory neuron

Efferent / Motor (neuron)

Motor neuron

Sensory or afferent neurons 

information input to the CNS

Motor or efferent neuron

• information output from the CNS

Somatic

• Neurons that connect the brain and spinal cord to the skeletal muscle.

• In charge of mostly voluntary movement but also skeletal muscle reflexes.

Autonomic

• Neurons that connect the brain and spinal cord to involuntary effectors →

  glands, cardiac muscle, & smooth muscle

Two branches in the (autonomic ns)

• Sympathetic

• Parasympathetic

Sympathetic

• Emergency / alert state (fight or flight)

Parasympathetic

Relaxation/ recovery state (rest and digest)

Enteric system

• Targets the digestive tract.

Sensory division 

Afferent division

Motor divison

Efferent division

Effectors can be

• muscles

• glands

NS organization

Neurons

• Cells that process & transmit information through electrical (impulse) & chemical signals (neurotransmitters)

 Neuroglia / glial cells 

• Cells that provide support to neurons

• Physical support (scaffolding)

• Supply of nutrients

• Regulate neuronal communication (synapse)

• Defense

Information can only travel from

• Dendrites to axon

Dendrites

Receives the information

Polar nervous cells

• Each side of the cell is different & has a specific funtion.

Polarity ensures

Transmission of the electric impulse in one single direction

NEURONS: Celular structure

• Dendrites

• Soma

• Axon

Dendrites

• Branched expansion of the cytoplasm.

• Area that receive the signals from pre-synaptic neurons.

Body of the neurons, containing the nucleus & most of the cytoplasm.

Axon

• Main projection from the soma

• Transmits the impulse.

• Variable length (from mm to m (1m)).

Classification according to morphology is based on the

• Number of neurites.

Unipolar

Sensory neuron

• Only one projection emerges from the soma

Pseudounipolar

• One projection then divides in two branches.

• Primary sensory neurons

Bipolar

• Two projections emerge from the soma in opposite directions → one axon & one dendrite.

• Retinal cells.

Multipolar

• Projection of one axon & multiple dendrites from the soma

• Most abundant in the brain

Two types of multipolar neurons

• Pyramidal cells.

• Purkinje Cells.

Pyramidal cells

Multipolar neuron typical of the cortex

Purkinje Cells

• Multipolar neuron typical of the cerebellum

Different functions of NEURONS

• Sensory neurons / Afferent neurons

• Interneurons

• Motoneurons / Efferent nuerons

Sensory neurons / Afferent neurons

• Neurons with sensory receptors (i.e. temperature) in their dendrites.

• Usually are pseudounipolar, with the soma located in the peripheral ganglia

• Transmit information (impulse) from the PNS to the CNS

Interneurons

• Neurons from the CNS that receive information from sensory neurons (at the dendrites) and connect with another interneuron or with a motor neuron.

• Usually multipolar.

• Integrate & relay information

Motoneurons / Efferent nuerons

• Neurons that conduct information (impulse) away from the CNS toward the target effectors.

• Usually are multipolar.

Tracing of axonal projection from 1 single interneuron

Multipolar neurons / Interneurons (two types)

• Pyramidal cells

• Purkinje cells

Parts of a neuron

Dendrites

Receives signals from other neuron cells

Cell body

• Contains the cell nucleus

Nucleus

• contains the genetic material (chromosome) of the neuron cell

Axon

• conducts electrical impulses along the neuron cell

Myeline sheet

• Insulates the axon

• Help to protect the neuron cell & speed up transmission of electrical signals

Axon terminal

• Transmits electrical & chemical signals to other neuron cells & effector cells