Human Biology Exam II Study Guide

What is compact bone composed of?

Osteons

What is spongy bone composed of?

Trabeculae

Where is spongy bone located in bones?

Inner part

Functions of Skeletal System

support, protection, movement, storage, blood cell production

Where is compact bone located in bones?

External layer

Periosteum

A dense fibrous membrane covering the surface of bones (except at their extremities) and serving as an attachment for tendons and muscles.

Bone cells

osteocytes

extracellular matrix

extracellular molecules secreted by cells that provides structural and biochemical support to the surrounding cells.

skeletal muscle

responsible for voluntary movement

Cardiac muscle

Involuntary muscle tissue found only in the heart, striated

Smooth muscle

involuntary muscle found in internal organs

Muscle tissue

A body tissue that contracts or shortens, making body parts move. Able to respond to stimulus

Muscle Cell

muscle fibers. long and slender and contains fibers that aid in contracting and relaxing

Structure of muscle organ

A muscle organ is composed of multiple muscle fibers bundled together within connective tissue layers

antagonistic pairs

muscles that serve opposite functions; when one muscle contracts, the other lengthens

Structure of Tendons

connective tissue, extending from muscle fascicle +fiber

Muscle polymer

myofibril

Muscle monomer

sacromere

Myofibrils

protein structures that make up muscle fibers. organelles within muscle fibers that are responsible for muscle contraction

myofilaments

The muscle contractile proteins, thin filaments actin and thick filaments myosin, of muscle cells

Sliding filament model

Idea of how a muscle fiber receives impulses from a nerve and causes contraction

CNS (central nervous system)

brain and spinal cord

Structures of neurons

cell body, dendrites, axon

Glial cell functions

help neurons regulate nutrient/ion concentration. To surround neurons and hold them in place. to insulate one neuron from another

Types of neurons

sensory, motor, interneurons

sensory neurons

neurons that carry incoming information from the sensory receptors to the brain and spinal cord

motor neurons

neurons that carry outgoing information from the brain and spinal cord to the muscles and glands

interneurons

neurons within the brain and spinal cord that communicate internally and intervene between the sensory inputs and motor outputs

Myelin sheath

Produces cerebrospinal fluid, scavenge dead cells, pathogen in brain, structural support for synapse, stimulate nerve growth.

Nerve Signal

electrical impulses that travel through nerve cells, or neurons, to transmit information

What Ions are crucial for a neuron to function?

K+, Na+, Cl-

State of neuron at rest

-70 mv

Na+/K+ pump

Active transporter that moves three Na+ out of a cell and two K+ into the cell against their respective concentration gradients.

More__ on the outside, more ___ on the inside

More Na+ on the outside, more K+ on the inside

Neuron function

sensory, motor, association

How does a electrical signal start?

when the membrane potential of a cell changes:
1. Inside of the cell used as a reference.
2. At rest, more negative inside then outside
3. moves three Na+ out of a cell and two K+ into the cell.

How does a electrical signal start?

Starts with small changes in voltage across cell membrane of dendrites and cell body. Small changes start when a stimulus causes a gated ion channel to open.

As positive comes into a neuron, mv becomes positive

mv = -70 to -60

Conduction of Nerve Impulses

At start of axon, summation of small changes depolarizes the neighboring region of axon membrane.

gated channels voltage

A change in the membrane potential causing the movement of certain charged regions on a channel protein, altering its shape.

Example: voltage-gated Na+ channel in excitable tissues

gated channels chemical

a molecule that binds to a specific receptor on a gated ion channel, causing it to open or close, thus allowing ions to flow across the cell membrane in response to a chemical signal

Ion concentration gradients

favor diffusion of potassium ions out of cell and sodium ions into cell. Potassium ions diffuse through leak channels more easily than sodium ions.

What starts an electrical signal along axon

excitatory postsynaptic potentials from a presynaptic neuron

Ion movement during an electrical signal

specialized channels in the plasma membrane open and allow rapid ion movement into or out of the cell

Neurotransmitters

chemical messengers that cross the synaptic gaps between neurons

Pain

an unpleasant sensory and emotional experience associated with actual or potential tissue damage

Endorphins

naturally occurring proteins that the body releases in response to pain. "morphine within"--natural, opiatelike neurotransmitters linked to pain control and to pleasure.

Opiates

opium and its derivatives, such as morphine and heroin; they depress neural activity, temporarily lessening pain and anxiety. However, opioids are able to act more quickly than endorphins because they can move directly into cells

Serotonin

Affects mood, hunger, sleep and arousal. Undersupply linked to depression.

Depression

genetic, biological, environmental, and psychological factors play a role in depression. Depression is NOT a consequence of low secretion.

SSRI

selective serotonin reuptake inhibitor

SSRI function

block reuptake of serotonin (Prozac, Zolaft, etc.)

Different types of treatments for depression

Different SSRIS (Prozac, Zolaft, etc.)

CNS (central nervous system)

brain and spinal cord

Protection of CNS

scalp and skin, skull and vertebral column, meninges, cerebrospinal fluid, blood brain barrier

Blood brain barrier

Blood vessels (capillaries) that selectively let certain substances enter the brain tissue and keep other substances out

White Matter

Bundles of myelinated zoons, communication, connects gray matter areas to each other to other parts of body.

Gray Matter

(outside) Cell bodies, dendrites, unmyelinated axons, integrates information to produce a response. 40% of braine, 94% of oxygen.

PNS (peripheral nervous system)

the sensory and motor neurons that connect the CNS to the rest of the body

Hypothalamus

Regulates homeostasis and autonomic functions.

CNS (central nervous system)

brain and spinal cord

Cerebrum

Largest part of brain, Area of the brain responsible for all voluntary activities of the body

Parietal lobe

A region of the cerebral cortex whose functions include processing information about touch.

Occipital lobe

visual processing

Sensory area

the site in the brain of the tissue that corresponds to each of the senses, with the degree of sensitivity related to the amount of tissue

Motor Area

A region of the frontal lobe involved in regulating movement

Primary motor area

sends impulses to skeletal muscles, located in frontal lobe

Premotor Cortex

The region controlling learned motor skills.

Prefrontal cortex

part of frontal lobe responsible for thinking, planning, and language

Thalamus

the brain's sensory switchboard, located on top of the brainstem; it directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla

Cerebellum

Brain region coordinating movement and balance.

Hippocampus

Involved in memory formation and spatial navigation.

Amygdala

Processes emotions and fear responses.

Brainstem Functions

Controls vital functions like breathing and heart rate.

Limbic System

Emotional and memory processing brain structures.

Reticular Activating Center

Regulates consciousness and alertness.

Somatic Nervous System

Controls voluntary muscle movements.

Sympathetic Nervous System

Prepares body for 'fight or flight' response.

Parasympathetic Nervous System

Promotes 'rest and digest' activities.

Dual-innervation

Organs receiving signals from both ANS divisions.

Sensory Reception

Detection of stimuli by sensory organs.

Perception

Interpretation of sensory information.

Adaptation

Decreased sensitivity to constant stimuli.

Transduction

Conversion of stimuli into neural signals.

Mechanoreceptors

Respond to mechanical pressure or distortion.

Chemoreceptors

Detect chemical stimuli like taste and smell.

Nociceptors

Pain receptors responding to harmful stimuli.

Olfactory Receptor Cells

Detect odor molecules for smell.

Taste Buds

Structures for detecting taste stimuli.

Neural Processing in Retina

Conversion of light into neural signals.

Aqueous Humor

Fluid maintaining eye shape and pressure.

Glaucoma

Condition caused by increased intraocular pressure.

Cornea

Transparent front part of the eye.

Sclera

White outer layer of the eyeball.

Myopia

Condition causing difficulty seeing distant objects.

Rods

Photoreceptors for low-light vision.

Cones

Photoreceptors for color vision.

Decussation

Crossing of nerve fibers in the brain.

Pinna

Outer ear structure capturing sound waves.

Tympanic Membrane

Eardrum vibrating in response to sound.