Physiology

Physiology definitions:

  • study of how anatomical features provide function

  • Knowledge of nature" - the study of how living organism's function

  • Understanding normal function to diagnose disease

  • Study of how and why parts function in living systems

Negative and Positive feedback -

negative feedback example is thermoregulation via sweat glands

positive feedback example is blood clotting, uterine contractions during childbirth

  • can be referred to antihomeostatic

CONPTT

  • consistent

  • observable

  • natural

  • predictable

  • testable

  • tentative science

Comparative approach

What is it?

  • ask similar questions of multiple species in order to determine shared vs unique traits

  • when mapped on a phylogenetic tree, pattern tells us if a trait evolved one or multiple times

Give an example of a question that might be answered using the comparative method.

  • comparing life expectancy between countries

Identify the common ancestor of any two living species on a phylogenetic tree.

what is “more closely related?”

  • how long ago did they share a common ancestor

  • which means it shared a common ancestor more recently

What specifically was one of the factors that increased to greater life expectancy.

  • vaccines, fam planning, work place safety, lower infant mortality rate

What is a limitation of correlative data?

Proximate

  • How?

  • mechanism (genetics, biochemistry)

  • development (environment)

Ultimate

  • Why?

  • function (adaptive value)

  • phylogeny (evolutionary constraint)

Biomolecules

what are the four classes of macromolecules

  • carbohydrates, lipids, proteins, nucleic acids

  • know the difference/ what do the structures look like

fats = triglycerides

Cells→ tissues→organs→organ systems

Central Dogma

  • defined as the idea that one gene or each gene codes for a protein or part of a protein

  • gene for each protein

  • WATCH 6/12 VIDEO

  • flow of genetic information, expression of genetic variation into phenotypic variation, functional roles of non-coding RNAs and other regulatory mechanisms continue to be characterized.

Most abundant cell type

  • red blood cells (erythrocytes)

Body compartments:

  • anatomical

    • cranial cavity

    • thoracic cavity

    • abdominopelvic cavity

  • Functional

    • extracellular fluid

      • blood plasma

      • interstitial fluid

        • the solutions carrying your cells

    • cells (intracellular fluid)

four main tissue types

  • epithelial

  • muscle

  • nervous

  • connective

epithelial

  • also lines your windpipe/trachea, esophagus

  • tight cell-cell junctions which eliminates extracellular space

  • high rate of regeneration

  • avascular

  • forms barriers and glands

muscle

  • primary function is movement

nervous tissue

  • highly specialized for electrical communication between cells

  • you can find it in the brain

    • has two cell types: neuron and neuroglia (glia)

connective tissue

  • most abundant and diverse

  • what does it do? contains non-living “extracellular matrix”

  • example of connective tissues

    • cartilage, fat, bone, blood

      • blood is because it travels to all part of the body

Bioenergetics and Metabolism

bioenergetics

  • the study of energy flow through biological systems

metabolism

  • all chemical reactions that occur within the organism

Why are enzymes needed to catalyze reactions?

  • they increase reaction rate, because alone it doesn’t occur fast enough to sustain human life

  • they don’t change

  • understand how they function

Understand the main steps of aerobic metabolism including where each takes place in the cell. Appreciate the massive increase in metabolic efficiency provided by oxidative phosphorylation. exergonic vs endergonic

  • glycolysis (cytoplasm), citric acid cycle (mitochondrion), electron transport system (mitochondria).

What might it mean if two cells have different amounts of biomolecules in their membranes? How might membrane composition relate to physiological function?

  • it forms a barrier between the cell and the external environment as it allows only selected molecules to pass through it and at the same time prevents entry of unwanted/ unnecessary substances.

exergonic

  • release energy

  • catabolic

  • break apart

endergonic

  • trap energy

  • stores

  • anabolic

  • build

factors that affect enzyme performance

  • temp

  • pH

  • enzyme concentration

  • substrate concentration

ways to regulate metabolism

  • control enzyme concentrations

    • confine enzymes within organelles, release as needed

  • modulate enzyme activity

    • modulators: factors that affect enzyme activity

    • cofactors are like adaptors for MACS

  • use different enzymes to catalyze reversible reactions

    • all reactions are reversible

  • maintain optimum ADP/ATP ratio

    • storage biomolecules for energy= glucose,glycogen,lipids

Cell membrane

  • phospholipid bilayer

  • non-polar tail (hydrophobic)

  • polar tail (hydrophilic)

General Functions:

  • physical isolation of intracellular and extracellular compartments

    • phospholipid bilayer

  • regulation of exchange

    • ions, nutrients, wastes, cell products

  • communication

  • structural support

Types of Membrane transport:

  • simple diffusion

    • movement from high concentration to low

  • facilitated diffusion

    • passive

    • high to low with aid of membrane-spanning proteins

    • use of channel protein which increases the permeability

  • osmosis

    • tonicity

    • low to high

  • active transport

    • requires input of energy from ATP

    • low to high

-ase = enzyme = protein

Types of cellular communication:

  • types of cell communication

  • chemical communication pathways

  • feedback loops

  • hormones as chemical messengers

chemical communication pathways:

  • gap junctions

    • form direct cytoplasmic connections between adjacent cells

    • found in smooth muscle

  • contact-dependent signals

    • require interaction between membrane molecules on two cells

  • “local” communication

    • intracrines- signals within a cell

    • autocrine - signaling with itself

    • paracrine- secreted by one cell and diffuse to adjacent cells

  • “long-distance” communication

    • neurotransmitters

    • neurocrines - any chemical messenger produced by a nueron

ectocrine- produced by an organism to affect another organism (pheromones)

  • not really on exam

Two Types of cellular receptors:

  • on the cell membrane

  • or intracellular (in nucleus or cytosol)

lipophilic vs lipophobic

  • lipophobic

    • fat afraid of water

    • only bonds outside the cell on the membrane

  • lipophilic

    • can bond in and out

Membrane receptors

  • direct

  • indirect 2nd

  • antagonists

    • works against it, prevents, blocks

    • blocks receptor activity

  • agonists

    • competes with primary ligand for binding receptor; causes biological response

    • also activates recepetor

ENDOCRINOLOGY

3 classical ways to investigate the function of a suspected endocrine tissue

  • remove the suspected gland

  • replace the hormone (or gland)

  • create excess hormone

what are the 3 major types of endocrine pathologies (disorders)

  • hypersecretion- too much hormone

  • hyposecretion- too little

  • abnormal target-tissue response - receptor or 2nd messenger problem

Describe how different chemical messengers (hydrophobic vs. hydrophilic) are transported, target.

  • hydrophilic is secreted through exocytosis

  • hydrophobic- crosses membranes easily

What is a hormone binding protein? Why and when are they necessary?

  • binds to hormones following secretion into blood stream

  • major purposes:

    • significantly improves the half-life of the protein

    • reduces minute to minute fluctuations in hormone concentration

Be able to classify different hormones based on the type of receptor they bind, where the hormone is produced, biochemical properties, and/or if their release is controlled by the brain

  • 1. based on the type of receptors they bind

    • lipophilic, lipophobic

  • 2. based on their release is controlled by CNS or not

    • hypothalamus → neurohormones (ex releasing hormone)

  • 3. based on where they are produced

  • 4. based on their chemical structure

chemical classifications of hormones:

  • peptides

    • short chains of amino acids

    • most common

    • made in rough er

    • insulin

    • released into circulation via excytosis

  • steroids

    • lipophilic, so they exit cell via simple diffusion

    • NEED to bind to carriers in blood

    • -Steroid hormones can bind receptors on the cell surface, in the cytosol, or in the nucleus.

  • amines

    • T3 T4 thyroid hormones

    • Modifications of single amino acids

    • All (except thyroid hormones) are made in advance in the cytosol

    • Released from cell via exocytosis

    • e.g. dopamine, norepinephrine, epinephrine

    • sub classes are thyroid and catecholines

Understand the basic differences between a peptide hormone binding a G-protein coupled receptor vs. a steroid hormone binding an intracellular receptor.

Describe five factors influencing the response of target cells to hormones.

  • affinity of receptor to hormone

  • concentration of hormone

  • number of receptors in/on cell

  • type of tissue

  • type of receptor

Describe a generic endocrine pathway (i.e. hormone axis).

  • hypothalamus target pituitary with a releasing hormone→pituitary releases a stimulating hormone into bloodstream→stimulating hormone causes distal (primary) endocrine glands to release hormone

  • the primary can be the one to feedback and turn off the hypothalamus

Name the four different hypothalamic-pituitary axes discussed in lecture. What are the main functions of each primary hormone?

  • thyroid (HPT)

    • T3 or T4

    • regulates metabolism

  • Adrenal gland (HPA)

    • • Controls secretion of cortisol from the adrenal cortex

      • Cortisol (steroid hormone)

  • Gonads

    • Follicle-stimulating hormone (FSH)

      • Leutinizing hormone (LH)

      • Controls hormones in the gonads (ovaries and testes)

      • Sex hormones (steroids)

  • Liver

Be able to diagnose a primary, secondary, or tertiary endocrine disorder based on the pattern of misregulated hormones and your understanding of how negative feedback should work.

  • 3) hypothalamus targets pituitary with a releasing hormone

    2) pituitary releases a stimulating hormone into. Bloodstream

    1) Stimulating hormone causes primary endocrine glands to release hormones

  • primary=

  • look where the “something going wrong” (like abnormal levels) is at to determine 1,2,3

Explain how a misregulated hormone might produce different symptoms depending on age.

  • because of the growth plate

When hormones travel from the hypothalamus to target cells in the anterior pituitary, the hypophyseal portal system helps to keep the hormone concentration _________

a. low

b. dilute

c. oxygenated

d. high